John Michael Croft
Kennesaw State University
Stat 3120-01
December 2, 2010
Final Project
Introduction
I want to begin with a proactive apology in advance for any lack of formality with regards to citing sources or references found throughout this paper. I feel complete formality unnecessary as I do not aspire to be the Bohr or Keynes of the statistical social science world and have no aspirations of this being published in any significant journals. I have attached two appendices: the first of which will contain all charts, figured, graphs, etc. that shall be referenced throughout, and the second will contain any and all SAS code used to report my findings. I created one variable on my own; however I obtained the idea from another data set found on a similar www.businessweek.com site. The variable is labeled as “SalperTuit” and is constructed from taking the median salary reported and dividing it by the cost of one semester for the corresponding college or university. This variable is intended to be viewed as a type of return on investment (ROI) with regards to starting median salary with respect to the cost of one semester. I also have constructed another variable found later in this report labeled as “TotCost” which is the cost per semester multiplied by the length of the program. My findings reported below primarily consist of analyzing select variables, while comparing the differences between public and private school graduates. The primary variables throughout my analyses are: School Type, Job Placement Grade, Teacher Quality Grade, Median Starting Salary, Length of Program, Cost per Semester, Total Cost, Salary per Tuition Dollar per Semester, and ROI Rank.
With regards to any lack of formality, I want to state the website in which I obtained my data from as far in advance as possible so not to mislead the reader as to the originality of the data that has been analyzed. The data set consist of the top 112 business undergrads schools in the United States and can be obtained at:
http://www.businessweek.com/interactive_reports/bschools_undergraduate_10rankings.html
This topic (public and private schools) has been of interest to me for a few years now. However it became of significant interest while I was interning for the Department of Justice in the summer of 2009 when the girl I was dating told me it cost her (or I’m sure her parents) $50,000 per year for tuition. I’ve also completed a similar analysis in the past on the top Research Universities and Liberal Arts Colleges located in the United States.
Research Hypotheses
The main purpose of this analysis is to show, hopefully, that private schools are overrated in relation to median starting salary. This is to say that while the difference in starting salaries for private school graduates may be significantly higher, it’s not so much higher as to justify the significantly higher tuition cost. And actually I feel the higher median starting salary one receives from attending a private school is nominal, and almost unwarranted, as compared to the significantly higher tuition cost. Below, I compare several variables based on type of schools, public or private, to help determine what encourages students to attend private schools over public schools. I also look at what helps to determine starting median salary between different school types.
Descriptive Statistics
Qualitative Variables
Figures: 29 and 30 are pie charts of percent frequencies for Teacher Quality Grade and Job Placement Grade. One should be aware the distributions appears identical with the mode of both being a grade of B.
According to Figure: 1 with respect to job placement grade, 19.82% or 22 schools have a grade of A+, 25.23% or 28 schools have a grade of A, 35.14% or 39 schools have a grade of B, and 19.82% or 22 schools have a grade of C. Grade B is the mode (the grade that occurs the most). According to Figure: 3 with respect to job placement grade, 14.29% or 9 public schools have a grade of A+, 26.98% or 17 public schools have a grade of A, 39.68% or 25 public schools have a grade of B, and 19.05% or 12 public schools have a grade of C. Again, grade B is the mode. According to Figure: 5 with respect to job placement grade, 27.08% or 13 private schools have a grade of A+, 22.92% or 11 private schools have a grade of A, 29.17% or 14 private schools have a grade of B, and 20.83% or 10 private schools have a grade of C. And again, grade B is the mode.
According to Figure: 7 with respect to teacher quality grade, 19.82% or 22 schools have a grade of A+, 25.23% or 28 schools have a grade of A, 35.14% or 39 schools have a grade of B, and 19.82% or 22 schools have a grade of C. Grade B is the mode. According to Figure: 9 with respect to teacher quality grade, 14.29% or 9 public schools have a grade of A+, 26.98% or 17 public schools have a grade of A, 39.68% or 25 public schools have a grade of B, and 19.05% or 12 public schools have a grade of C. And again, grade B is the mode. According to Figure: 11 with respect to teacher quality grade, 27.08% or 13 private schools have a grade of A+, 22.92% or 11 private schools have a grade of A, 29.17% or 14 private schools have a grade of B, and 20.83% or 10 private schools have a grade of C. And again, grade B is the mode.
Quantitative Variables
Figure 21 shows the descriptive statistics for the quantitative variables analyzed for this report. Median starting salary has a mean of $48,310 and a median of $48,500 with a minimum of $36,000 and a maximum of $62,000 as well as a standard deviation of $5650.05. Starting salary per one tuition dollar per semester has a mean of $4.05 and a median of $4.14 with a minimum of $1.13 and a maximum of $11.70 as well as a standard deviation of $2.74. Cost per semester has a mean of $19,882.39 and a median of $11,732 with a minimum of $3,738 and a maximum of $41,610 as well as a standard deviation of $13,605. Length of program has a mean of 3.58 years and a median of 4 years with a minimum of 2 years and a maximum of 4 years as well as a standard deviation of .803 years. Total program cost has a mean of $74,470 and a median of $46,928 with a minimum of $7,476 and a maximum of $166,440 as well as a standard deviation of $55,632. ROI rank has a mean and median of 56 with a minimum of 1 and a maximum of 111 as well as a standard deviation of 32.19 places.
Figure 22 shows descriptive statistics for the same quantitative variables discussed above from Figure 21, however they are broken down by school type. I would like to point out some seemingly significant aspects of Figure 22; however I encourage the reader to take a complete look in appendix I if interested above and beyond what I report here. On average, the starting salary per tuition dollar per semester for public schools is $4.22 higher than private schools. On average, private schools cost $25,710 more per semester than public schools. On average, private school total program cost is approximately $102,000 more than public schools. And on average, the ROI rank is 53 spots lower for public schools over private schools with lower rankings being better.
Figure 31 is a bar chart of starting median salary. The distribution appears to be normal with the mean being a preferred benchmark over the median. Figure 35 is a bar chart of starting median salary by type of school. The distribution for each appears to be normal with the mean being a preferred benchmark over the median. Private school students have a higher maximum while public school students have a lower minimum, however the mean of both appear to be similar.
Figure 32 is a bar chart of starting salary per tuition dollar spent per semester. The distribution appears to not be normal but seems to be decreasing at a decreasing rate, on average. The median would be a better benchmark for starting salary per tuition dollar per semester. Figure 36 is a bar chart of starting salary per tuition dollar per semester by school type. It shows that private school students have a fairly low starting salary per tuition dollar spent per semester when compared to that of public school students.
Figure 33 is a bar chart of tuition cost per semester. The distribution appears to not be normal and appears to be bimodal with the modes appearing towards the minimum and maximum of the distribution. The median would be a better benchmark for tuition cost per semester. Figure 37 is a bar chart of tuition cost per semester by school type. It shows that private school students appear to pay a much more in tuition as compared with public school students. With the exception of a small percent of private schools, it appears the maximum cost for public schools is lower than the minimum for a private school.
Figure 34 is a bar chart of total tuition cost. The distribution appears to not be normal and appears to be bimodal with the modes appearing towards the minimum and maximum of the distribution. The median would be a better benchmark for tuition cost per semester. Figure 38 is a bar chart of total tuition cost by school type. It shows that private school students appear to pay a much more in tuition as compared with public school students. Again, with the exception of a small percent of private schools, it appears the maximum cost for public schools is lower than the minimum for a private school.
Results
From the previous section, we notice, on average, that public and private undergrad schools have grades of B for job placement grade and teacher quality. Again, I would like to point out that the results for job placement grade and teacher quality grade appear identical and may be highly correlated.
According to Figure: 2, we are 95% confident the true population proportion of top business undergrad schools that have a job placement grade of A+ is between 10.07% and 29.57%. According to Figure: 4, we are 95% confident the true population proportion of top business undergrad public schools that have a job placement grade of A+ is between 2.93% and 25.64%. According to Figure: 6, we are 95% confident the true population proportion of top business undergrad private schools that have a job placement grade of A+ is between 10.56% and 43.61%. From figure 13, we are 95% confident the true population proportion difference between private school and public schools with job placement grades of A or higher is not significantly different since the interval runs from -9.52% and 27.38% in which 0% falls between.
According to Figure: 8, we are 95% confident the true population proportion of top business undergrad schools that have a teacher quality grade of A+ is between 10.07% and 29.57%. According to Figure: 10, we are 95% confident the true population proportion of top business undergrad public schools that have a teacher quality grade of A+ is between 2.93% and 25.64%. According to Figure:
12, we are 95% confident the true population proportion of top business undergrad private schools that have a teacher quality grade of A+ is between 10.56% and 43.61%. From figure 14, we are 95% confident true population difference between private school and public schools with teacher quality grades of A or higher is significantly different, with a difference between 36.80% and 68.76% with private schools being more likely to have higher grades.
From Figures 15-20, we see the 95% confidence intervals for the quantitative variables analyzed for this report, all of which appear to be significant with respect to the top undergrad business school by school type (public or private), as well as the difference between the types which all also appear to be significant.
According to Figure: 15, we are 95% confident the true population mean median starting salary for private schools is between $48,585 and $51,899 with a mean of $50,242 compared to $45,534 and $48,145 with a mean of $46,840 for public schools. Furthermore we see the true population difference of public schools and private schools is between $1316 and $5489 with an average difference of $3402 where private schools having higher starting salaries.
According to Figure: 16, we are 95% confident the true population mean cost per semester for private schools is between $32,650 and $36,300 with a mean of $34,474 compared to $8,052 and $9,477 with a mean of $8,764 for public schools. Furthermore we see the true population difference of public schools and private schools is between $23,762 and $27,659 with an average difference of $25,710 where private schools are more expensive.
According to Figure: 17, we are 95% confident the true population mean program length for private schools is between 3.65 and 5 years with a mean of 3.81 years compared to 3.17 and 3.63 years with a mean of 3.40 years for public schools. Furthermore we see the true population difference of public schools and private schools is between .13 and .69 years with an average difference of .42 years where private schools take longer to complete.
According to Figure: 18, we are 95% confident the true population mean starting salary per one tuition dollar per one semester for private schools is between $1.23 and $2.09 with a mean of $1.66 compared to $5.38 and $6.37 with a mean of $5.88 for public schools. Furthermore we see the true population difference of public schools and private schools is between $3.57 and $4.87 with an average difference of $4.22 with public schools being paid more per tuition dollar spent per semester.
According to Figure: 19, we are 95% confident the true population mean ROI rank for private schools is between 80.87 and 91.54 with a mean of 86.21 compared to 28.36 and 37.61 with a mean of 32.98 for public schools. Furthermore we see the true population difference of public schools and private schools is between 46.24 and 60.21 places with an average difference of 53.22 places where public schools have better ROI Rankings (given a lower ranking is better).
According to Figure: 20, we are 95% confident the true population mean difference of Total Tuition and Starting Median Salary for private schools is between $73,807 and $90,752 with a mean of $82,279 (meaning on average private school students spend $82,279 more on tuition than they make in the first year of employment) compared to $13,078 and $20,117 with a mean of $16,598 for public schools (meaning on average public school students make $16,568 more the first year of employment than their total tuition). Furthermore we see the true population difference of public schools and private schools is between $89,756 and $107,998 with an average difference of $98,877 where public schools net, on average, $98,877 more than private schools, the first year of employment.
From Figure 23, we see that best linear model to explain starting median salary as explained by cost per semester is:
Med_Sal = 45,118 + .1606(Cost)
On average students will start out making $45,118 with an additional $16.06 per $100 spent on tuition per semester. Both the intercept and the slope parameter estimates appear to be significant, with 14.17% of the variation in Starting Median Salary being explained by our model. However, I stop short of saying this is the best model possible as a linear relationship may not be the best representation.
Figure 24 is a scatter plot of starting median salary and cost of tuition per semester. There does appear to be a general increase in median salary as cost per semester increases, however, again there may not be a linear relationship. Starting median salary appears to increase initially as cost per semester increases, however it then flattens out, begins to decrease and then resumes increasing. A cubic model may be a better fit to explain the relationship show in this figure. I also want to say this may even be a discontinuous graph.
Figure 25 shows a scatter plot of cost (as the independent variable) plotted with the residual value from predicting starting median salary. The residuals appear to be concentrated towards the bottom and towards the top of the scatter plot with an obvious gap in the middle. The gap appears to separate the public schools from the private schools. Further analyses would need to be conducted to make any meaningful conclusions to this figure.
From Figure 26, we see that best linear model to explain starting salary per tuition dollar per semester as explained by cost per semester is:
SalperTuit = 7.552 - .0001759(Cost)
On average students will start out making $7.55 per tuition dollar per semester spent minus $.1759 per $1,000 spent on tuition per semester. Both the intercept and the slope parameter estimates appear to be significant with our model explaining 76.38% of the variation in Sal per Tuition Dollar per Semester. However, this is probably not the best model possible as a linear relationship may not be the best way to model this data.
Figure 27 shows a scatter plot between starting salary per tuition dollar per semester and cost per semester. I feel confident in saying that this relationship is not linear and further analyses are required to make meaningful statement about this relationship. The figure shows that starting salary per tuition dollar per semester is decreasing at a decreasing rate as cost per semester increase with some type of log linear relationship.
Figure 28 is one of the more interesting graph as it show a hyperbolic relationship between cost per semester (as the independent variable) and the residuals from the prediction of salary per tuition dollar spent per semester. Further analyses are needed to make a meaningful conclusion, however the relationship does not appear normal or random.
Conclusion
In conclusion, I would like to point out some significant points of interested noted in the above sections. Compared to public schools, private school programs take, on average, almost six months longer to complete, and their students start out making $3402 more their first year of employment, however tuition cost $25, 710 more per semester while public schools grads making $4.22 more per tuition dollar spent per semester. For a four year program, it would cost a private school graduate over $100,000 more than a public school graduate and take approximately four years to recoup the tuition with a starting salary of $52,000 where the public school graduate recoups her tuition the first year. By the time a private school graduate recoups her tuition, a public school graduate will have netted approximately $157,000 more over a four year period.
I also want to again point out the true population difference of public schools and private schools is between $89,756 and $107,998 with an average difference of $98,877 where public schools net, on average, $98,877 more than private schools, the first year of employment.
The author is a graduate of a public school, thus making his opinion of private schools possibly somewhat bias, but I hope my findings somewhat justify this opinion.
Further Research
I want to encourage any and all possible further research on this topic as there several other variables that need to be analyzed in relation to median starting salary that have not been addressed in this report. If not for higher starting salaries, why do students choose to attend private schools? Some areas of interest may be to study the correlations and other relationships with: acceptance into better grad schools programs, time it takes to get a job after completion of undergrad program, ability to be more selective in who one works for, how early and often one might receive a raise, ability to learn from more knowledgeable professors. This is by no means an exhaustive list as there are several more one can chose to research.
Appendix I
Figure 1: Frequency Chart of Job Placement Grade
Grade Frequency PercentCumulativeFrequency
CumulativePercent
A+ 22 19.82 22 19.82
A 28 25.23 50 45.05
B 39 35.14 89 80.18
C 22 19.82 111 100.00
Figure 2: Z-Test for Job Placement Grade = A+
Proportion 0.1982
ASE 0.0378
95% Lower Conf Limit 0.1007
95% Upper Conf Limit 0.2957
Exact Conf Limits
95% Lower Conf Limit 0.1110
95% Upper Conf Limit 0.3122
Test of H0: Proportion = 0.5
ASE under H0 0.0475
Z -6.3594
One-sided Pr < Z <.0001
Two-sided Pr > |Z| <.0001
Figure 3: Frequency distribution of Public Schools Job Placement Grade
Grade Frequency PercentCumulativeFrequency
CumulativePercent
A+ 9 14.29 9 14.29
A 17 26.98 26 41.27
B 25 39.68 51 80.95
C 12 19.05 63 100.00
Figure 4: Public School Job Placement Grade = A+
Proportion 0.1429
ASE 0.0441
95% Lower Conf Limit 0.0293
95% Upper Conf Limit 0.2564
Exact Conf Limits
95% Lower Conf Limit 0.0518
95% Upper Conf Limit 0.2904
Test of H0: Proportion = 0.5
ASE under H0 0.0630
Z -5.6695
One-sided Pr < Z <.0001
Two-sided Pr > |Z| <.0001
Figure 5: Frequency distribution Private School Job Placement Grade
Grade Frequency PercentCumulativeFrequency
CumulativePercent
A+ 13 27.08 13 27.08
A 11 22.92 24 50.00
B 14 29.17 38 79.17
C 10 20.83 48 100.00
Figure 6: Private School Job Placement Grade = A+
Proportion 0.2708
ASE 0.0641
95% Lower Conf Limit 0.1056
95% Upper Conf Limit 0.4361
Exact Conf Limits
95% Lower Conf Limit 0.1251
95% Upper Conf Limit 0.4633
Test of H0: Proportion = 0.5
ASE under H0 0.0722
Z -3.1754
One-sided Pr < Z 0.0007
Two-sided Pr > |Z| 0.0015
Figure 7: Frequency Chart: Teacher Quality Grade
Teacher Quality Grade Frequency PercentCumulativeFrequency
CumulativePercent
A+ 22 19.82 22 19.82
A 28 25.23 50 45.05
B 39 35.14 89 80.18
C 22 19.82 111 100.00
Figure 8: Teacher Quality Grade = A+
Proportion 0.1982
ASE 0.0378
95% Lower Conf Limit 0.1007
95% Upper Conf Limit 0.2957
Exact Conf Limits
95% Lower Conf Limit 0.1110
95% Upper Conf Limit 0.3122
Test of H0: Proportion = 0.5
ASE under H0 0.0475
Z -6.3594
One-sided Pr < Z <.0001
Two-sided Pr > |Z| <.0001
Figure 9: Frequency Chart: Public School Teacher Quality Grades
Teacher Quality Grade Frequency PercentCumulativeFrequency
CumulativePercent
A+ 6 9.52 6 9.52
A 8 12.70 14 22.22
B 28 44.44 42 66.67
C 21 33.33 63 100.00
Figure 10: Z-Test for Public School Teacher Quality Grade = A+
Proportion 0.0952
ASE 0.0370
95% Lower Conf Limit 0.0000
95% Upper Conf Limit 0.1905
Exact Conf Limits
95% Lower Conf Limit 0.0251
95% Upper Conf Limit 0.2300
Test of H0: Proportion = 0.5
ASE under H0 0.0630
Z -6.4254
One-sided Pr < Z <.0001
Two-sided Pr > |Z| <.0001
Figure 11: Frequency Chart: Private School Teacher Quality Grades
Teacher Quality Grade Frequency PercentCumulativeFrequency
CumulativePercent
1A 16 33.33 16 33.33
2A 20 41.67 36 75.00
3B 11 22.92 47 97.92
4C 1 2.08 48 100.00
Figure 12: Z-Test for Private School Teacher
Quality Grade = A+
Proportion 0.3333
ASE 0.0680
99% Lower Conf Limit 0.1581
99% Upper Conf Limit 0.5086
Exact Conf Limits
99% Lower Conf Limit 0.1719
99% Upper Conf Limit 0.5286
Test of H0: Proportion = 0.5
ASE under H0 0.0722
Z -2.3094
One-sided Pr < Z 0.0105
Two-sided Pr > |Z| 0.0209
Figure 13: Job Placement Grade by School Type
School Type Job Placement Grade
FrequencyPercentRow PctCol Pct A or A+ B or C Total
Private 2421.6250.0048.00
2421.6250.0039.34
4843.24
Public 2623.4241.2752.00
3733.3358.7360.66
6356.76
Total 5045.05
6154.95
111100.00
A or A+ Risk Estimates
Risk ASE(Asymptotic) 95%Confidence Limits
(Exact) 95%Confidence Limits
Private 0.5000 0.0722 0.3586 0.6414 0.3523 0.6477
Public 0.4127 0.0620 0.2911 0.5343 0.2901 0.5438
Total 0.4505 0.0472 0.3579 0.5430 0.3559 0.5478
Difference 0.0873 0.0952 -0.0992 0.2738
Difference is (Private - Public)
Figure 14: Teacher Quality Grade by School Type
School Type Teacher Quality Grade
FrequencyPercentRow PctCol Pct A or A+ B or C Total
Private 3632.4375.0072.00
1210.8125.0019.67
4843.24
Public 1412.6122.2228.00
4944.1477.7880.33
6356.76
Total 5045.05
6154.95
111100.00
A or A+ Risk Estimates
Risk ASE(Asymptotic) 95%Confidence Limits
(Exact) 95%Confidence Limits
Private 0.7500 0.0625 0.6275 0.8725 0.6040 0.8636
Public 0.2222 0.0524 0.1196 0.3249 0.1272 0.3446
Total 0.4505 0.0472 0.3579 0.5430 0.3559 0.5478
Difference 0.5278 0.0815 0.3680 0.6876
Difference is (Private - Public)
Figure 15: Median Starting Salary by School Type
Type Method Mean 95% CL Mean Std Dev 95% CL Std Dev
Private 50241.8 48585.0 51898.7 5706.0 4750.1 7147.2
Public 46839.3 45533.8 48144.7 5183.6 4410.1 6288.5
Diff (1-2) Pooled 3402.5 1346.3 5458.7 5415.0 4781.7 6243.2
Diff (1-2) Satterthwaite 3402.5 1316.1 5489.0
Figure 16: Tuition Cost per Semester by School Type
Type Method Mean 95% CL Mean Std Dev 95% CL Std Dev
Private 34474.7 32649.9 36299.4 6284.2 5231.4 7871.5
Public 8764.4 8052.3 9476.6 2827.6 2405.7 3430.3
Diff (1-2) Pooled 25710.2 23946.4 27474.1 4645.0 4101.8 5355.4
Diff (1-2) Satterthwaite 25710.2 23761.9 27658.6
Figure 17: Length of Program by School Type
Type Method Mean 95% CL MeanStd De
v 95% CL Std Dev
Private 3.8125 3.6468 3.9782 0.5708 0.4752 0.7150
Public 3.3968 3.1682 3.6254 0.9077 0.7722 1.1012
Diff (1-2) Pooled 0.4157 0.1193 0.7120 0.7804 0.6892 0.8998
Diff (1-2) Satterthwaite 0.4157 0.1362 0.6951
Figure 18: Starting Salary per Tuition Dollar per Semester by School Type
Type Method Mean 95% CL Mean Std Dev 95% CL Std Dev
Private 1.6584 1.2298 2.0869 1.4759 1.2286 1.8486
Public 5.8781 5.3846 6.3716 1.9595 1.6671 2.3772
Diff (1-2) Pooled -4.2197 -4.8908 -3.5486 1.7673 1.5606 2.0376
Diff (1-2) Satterthwaite -4.2197 -4.8660 -3.5734
Figure 19: ROI Rank by School Type
Type Method Mean 95% CL Mean Std Dev 95% CL Std Dev
Private 86.2083 80.8693 91.5474 18.3870 15.3066 23.0312
Public 32.9841 28.3607 37.6075 18.3580 15.6188 22.2713
Diff (1-2) Pooled 53.2242 46.2485 60.1999 18.3705 16.2221 21.1801
Diff (1-2) Satterthwaite 53.2242 46.2410 60.2074
Figure 20: Difference of Total Tuition and Starting Median Salary by School Type
Type Method Mean 95% CL Mean Std Dev 95% CL Std Dev
Private 82279.4 73806.5 90752.3 29179.8 24291.2 36550.0
Public -16597.8 -20117.3 -13078.2 13975.1 11889.9 16954.1
Diff (1-2) Pooled 98877.1 90573.1 107181 21868.5 19311.0 25213.1
Diff (1-2) Satterthwaite 98877.1 89755.9 107998
Figure 21: Descriptive Statistics
Variable Label Mean Median Std Dev Minimum Maximum
Median SalarySalary / TuitionCost per Sem.Length of Prog.Total Prog. CostROI Rank
Med_SalSalperTuitCostLengthTotCostROI_Rank
48310.644.05
19882.393.58
74470.5656.00
48500.004.14
11732.004.00
46928.0056.00
5650.052.74
13604.830.803
55632.2432.187
36000.001.127
3738.002.00
7476.001.00
62000.0011.70
41610.004.00
166440.00111.00
Figure 22: Descriptive Statistics by School Type
TypeN
Obs Variable Label Mean Median Std Dev Minimum Maximum
Private 48 Median SalarySalary / TuitionCost per Sem.Length of Prog.Total Prog. CostROI Rank
Med_SalSalperTuitCostLengthTotCostROI_Rank
50241.811.658
34474.693.812
132521.1986.208
50000.001.422
35950.004.00
142612.0087.50
5705.991.475
6284.250.570
30481.9118.385
40000.001.127
4325.002.00
8650.002.00
62000.0011.560
41610.004.00
166440.00111.00
Public 63 Median SalarySalary / TuitionCost per Sem.Length of Prog.Total Prog. CostROI Rank
Med_SalSalperTuitCostLengthTotCostROI_Rank
46839.275.878
8764.443.396
30241.5132.984
46500.005.368
8532.004.00
28976.0033.00
5183.561.959
2827.580.907
13783.4418.357
36000.002.831
3738.002.00
7476.001.00
59000.0011.70
16800.004.00
67200.0064.00
Figure 23: Regression Model of Median Salary on Cost
Variable Label DFParameter
EstimateStandard
Error t Value Pr > |t|95% Confidence
Limits
Intercept Intercept
1 45118 882.50016
51.12 <.0001 43369 46867
Cost Cost 1 0.16059 0.03668 4.38 <.0001 0.08789 0.23330
Root MSE 5234.37720 R-Square 0.1495
Dependent Mean
48311 Adj R-Sq 0.1417
Coeff Var 10.83483
Figure 24: Scatter plot of Median Salary and Cost per Semester
Med_Sal
30000
40000
50000
60000
70000
Cost
0 10000 20000 30000 40000 50000
Figure 25: Scatter Plot of Cost per Semester and Residuals
Cost
0
10000
20000
30000
40000
50000
Residual
-20000 -10000 0 10000 20000
Figure 26: Regression Model of Salary per Tuition Dollar per Semester on Cost
Variable Label DFParameter
EstimateStandard
Error t ValuePr > |
t| 95% Confidence Limits
Intercept Intercept
1 7.55232 0.22549 33.49 <.0001 7.10542 7.999
Cost Cost 1 -0.0001759 0.00000937 -18.78 <.0001 -0.000194 -0.000157
Root MSE 1.33742 R-Square 0.7638
Dependent Mean 4.05335 Adj R-Sq 0.7617
Coeff Var 32.99552
Figure 27: Scatter plot of Salary per Tuition Dollar per Semester and Cost per Semester
SalperTuit
1
2
3
4
5
6
7
8
9
10
11
12
Cost
0 10000 20000 30000 40000 50000
Figure 28: Scatter Plot of Cost per Semester and Residuals
Cost
0
10000
20000
30000
40000
50000
Residual
-3 -2 -1 0 1 2 3 4 5
Figure 29: Pie Chart of Job Placement Grade
PERCENT of Job_Placement_grade
A25.23%
A+
Figure 30: Pie Chart of Teacher Quality Grade
PERCENT of Teacher_Quality_Grade
A25.23%
A+
Figure 31: Bar Chart of Starting Median Salary ($)
37500 40500 43500 46500 49500 52500 55500 58500 61500
0
5
10
Figure 32: Bar Chart of Starting Salary per Tuition Dollar Spent per Semester ($)
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Figure 33: Bar Chart of Cost of Tuition per Semester ($)
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Figure 34: Bar Chart of Total Cost of Tuition ($)
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Figure 35: Bar Chart of Starting Median Salary by Type ($)
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Figure 36: Bar Chart of Starting Salary per Tuition Dollar per Semester by Type($)
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Figure 37: Bar Chart of Cost of Tuition per Semester by Type ($)
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Figure 38: Bar Chart of Total Cost of Tuition by Type ($)
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Appendix II
proc print data = jmc.tc;run;
Data Jmc.tc1;set jmc.tc;if Job_Placement_grade = "A+" then Job_Placement_grade = "1A+";else if Job_Placement_grade = "A" then Job_Placement_grade = "2A";else if Job_Placement_grade = "B" then Job_Placement_grade = "3B";else if Job_Placement_grade = "C" then Job_Placement_grade = "4C";else Job_Placement_grade = "Missing";Run;
proc print data = jmc.tc1;run;
ods rtf;Proc Freq data=jmc.tc1;Tables Job_Placement_grade/binomial;Run;
proc Freq data=jmc.tc1;Tables Job_Placement_grade/binomial;where type = "Public";Run;
proc Freq data=jmc.tc1;Tables Job_Placement_grade/binomial;
where type = "Private";Run;ods rtf close;
Data Jmc.tc2;set jmc.tc;if Teacher_Quality_Grade = "A+" then Teacher_Quality_Grade = "1A+";else if Teacher_Quality_Grade = "A" then Teacher_Quality_Grade = "2A";else if Teacher_Quality_Grade = "B" then Teacher_Quality_Grade = "3B";else if Teacher_Quality_Grade = "C" then Teacher_Quality_Grade = "4C";else Teacher_Quality_Grade = "Missing";Run;
ods rtf;Proc Freq data=jmc.tc2;Tables Teacher_Quality_Grade/binomial;Run;
Proc Freq data=jmc.tc2;Tables Teacher_Quality_Grade/binomial;where type = "Public";Run;
Proc Freq data=jmc.tc2;Tables Teacher_Quality_Grade/binomial;where type = "Private";Run;ods rtf close;
Data Jmc.tc3;set jmc.tc;if Teacher_Quality_Grade = "A+" then Teacher_Quality_Grade = "1Yes";else if Teacher_Quality_Grade = "A" then Teacher_Quality_Grade = "1Yes";else if Teacher_Quality_Grade = "B" then Teacher_Quality_Grade = "2No";else if Teacher_Quality_Grade = "C" then Teacher_Quality_Grade = "2No";else Teacher_Quality_Grade = "Missing";Run;
ods rtf;Proc freq data = jmc.tc3;tables type*Teacher_Quality_Grade/riskdiff;run;ods rtf close;
Data Jmc.tc4;set jmc.tc;if Job_Placement_grade = "A+" then Job_Placement_grade = "1Yes";else if Job_Placement_grade = "A" then Job_Placement_grade = "1Yes";else if Job_Placement_grade = "B" then Job_Placement_grade = "2No";else if Job_Placement_grade = "C" then Job_Placement_grade = "2No";else Job_Placement_grade = "Missing";Run;
ods rtf;Proc freq data = jmc.tc4;tables type*Job_Placement_grade/riskdiff;run;ods rtf close;
ods rtf;proc ttest data = jmc.tc;var Med_Sal;class type;run;
proc ttest data = jmc.tc;var Cost;class type;run;
proc ttest data = jmc.tc;var Length;class type;run;
proc ttest data = jmc.tc;var SalperTuit;class type;run;proc ttest data = jmc.tc;var ROI_Rank;class type;run;ods rtf close;
data jmc.tc;set jmc.tctotcost;TotCost = cost*length;run;
data jmc.tcdiff;set jmc.tctotcost;diff = TotCost-Med_Sal;run;
ods rtf;proc ttest data = jmc.tcdiff;var diff;class type;run;ods rtf close;
ods rtf;proc ttest data = jmc.tctotcost;paired Med_Sal*totcost;where type = "Public";run;
proc ttest data = jmc.tctotcost;
paired Med_Sal*totcost;where type = "Private";run;ods rtf close;
ods rtf;proc reg data = jmc.tcnew;model Med_sal = cost / clb clm p r;output out = Med_salpredictions_cost p = pred r = resids;run;
proc gplot data = jmc.tcnew; plot Med_sal*cost;run;
proc gplot data = Med_salpredictions_cost; plot cost*resids;run;ods rtf close;
ods rtf; proc reg data = jmc.tcnew;model Med_Sal = SalperTuit/ clb clm p r;output out = Med_salpredictions_SalperTuit p = pred r = resids;run;
proc gplot data = jmc.tcnew; plot Med_sal*SalperTuit;run;
proc gplot data = Med_salpredictions_SalperTuit; plot salpertuit*resids;run;ods rtf close;
ods rtf;proc reg data = jmc.tcnew;model SalperTuit = cost / clb clm p r;output out = SalperTuitpredictions_cost p = pred r = resids;run;
proc gplot data = jmc.tcnew; plot SalperTuit*cost;run;
proc gplot data = SalperTuitpredictions_cost; plot cost*resids;run;ods rtf close;
ods rtf;proc reg data = jmc.tcnew;model SalperTuit = Med_Sal / clb clm p r;output out = SalperTuitpredictions_Medsal p = pred r = resids;run;
proc gplot data = jmc.tcnew;
plot SalperTuit*med_sal;run;
proc gplot data = SSalperTuitpredictions_Medsal; plot med_sal*resids;run;ods rtf close;
ods rtf;PROC MEANS DATA=jmc.tctotcost mean median std clm min max skew;variable med_sal;variable salpertuit;variable cost;variable length;variable totcost;variable ROI_Rank;RUN;
PROC MEANS DATA=jmc.tctotcost mean median std clm min max skew;variable med_sal;variable salpertuit;variable cost;variable length;variable totcost;variable ROI_Rank;class type;RUN;ods rtf close;
ods rtf;proc gchart data = jmc.tctotcost; pie Job_Placement_grade / type = pct; legend; Run; Quit;
proc gchart data = jmc.tctotcost; pie Teacher_Quality_Grade / type = pct; legend; Run; Quit;
Proc Univariate data=jmc.tctotcost plots; variable med_sal;variable salpertuit;variable cost;variable length;variable totcost;variable ROI_Rank;
Histogram;Run;
Proc Univariate data=jmc.tctotcost plots; variable med_sal;variable salpertuit;variable cost;variable length;variable totcost;variable ROI_Rank;class type;Histogram;Run; ods rtf close;