MA 2113 Homework #1

Table 1. Count of oak tree types on a selected study site on Noxubee National Wildlife Refuge.

Species (Class) Total

(Frequency) Rel Freq %

White Oak 42

Water Oak 8

Red Oak 16

Scarlet Oak 11

Post Oak 7

Northern Red

Oak

16

Cherrybark Oak 4

1. What type of data is this? Quantitative or Qualitative

2. Calculate the relative frequency and percentage of each type.

3. Construct a bar graph of the relative frequency of types of oak.

Table 2. Test scores from Exam 1 from a Marine Biology class.

4. What type of data is this? Quantitative or Qualitative

5. Calculate relative frequency of scores by class. You determine the class intervals, so you do not have

to use all rows or you can add some.

6. Construct a histogram of relative frequency of scores by class.

92 78 73 72 50

79 76 51 78 94

72 89 27 53 88

62 71 91 90 83

83 71 75 41 94

76 94 87 89 71

43 90 83 87 93

98 75 50 87 74

85 87 63 86

44 84 89 77

Class Freq Rel Freq %

MA 2113 Homework #2

Be sure to show all tables and calculations!

Top 30 tacklers in the NFL in 2017.

1. What is the mean and standard deviation in tackles for these players?

2. What is the median and Five-number Summary (quartiles) for PPG for these players?

Player Tackles

Antonio Morrison 108

Blake Martinez 144

Bobby Wagner 133

Brandon Marshall 106

C.J. Mosley 132

Christian Kirksey 138

Deion Jones 138

Demario Davis 135

Devin McCourty 97

Eric Kendricks 113

Jahleel Addae 96

Jarrad Davis 96

Joe Schobert 144

Jon Bostic 97

K.J. Wright 108

Karlos Dansby 95

Keanu Neal 116

Kiko Alonso 115

Kwon Alexander 97

Landon Collins 104

Lavonte David 101

Luke Kuechly 125

Matthias Farley 98

Preston Brown 144

Reshad Jones 122

Sean Lee 101

Tahir Whitehead 110

Telvin Smith 102

Wesley Woodyard 124

Zach Brown 127

MA 2113 Homework #3

1. Determine outliers, if any, and construct a boxplot for the following data.

Number of games played by Wayne Gretzky (pro hockey player) in each of his 20 seasons.

2. For the following equations provide:

a) y‐intercept and slope

b) a graph of the equation (plot at least 2 points other than the y‐intercept)

y = 4 + 3x

y = 7 – 6x

y = 0.5x – 2

y = x – 2

79 80 80 80 74

80 80 79 64 78

73 78 74 45 81

48 80 82 82 70

ST 2113 Homework #4

1. Calculate a regression equation using the (x, y) data below (8 points). We are interested to see if a

student’s grade on Exam 1 (x) has any relationship to final average (y) for a statistics class.

To check if you have done your work correctly, this should be your answer:

ŷ = 60.3 + 0.35 x

Of course, show all your work.

Exam1 (x) Final (y)

76 88.7

110 99.6

73 81.3

77 85.9

32 68.5

107 98.5

79 95.6

62 90.5

94 98.2

90 77.4

93 95.6

2. Graph a scatterplot of the data along with the regression line from the regression equation (2 points).

MA 2113 Homework #5

1. Compute the coefficient of determination for the regression equation calculated using the data

below.

Age, x, in years and price, y, in dollars (divided by 100) from a random sample of 12 Honda

Accords listed for sale on AutoTrader.com within 100 miles of Meridian, MS.

Hint: You will need to first calculate the regression equation as you did in Homework #4. You should get

b1 = – 7.67 and b0 = 179.63. For the regression coefficient below, you should get r2 = 0.7889 or 78.9%.

Age (x ) Price (y )

14 56.0

4 99.8

10 110.0

3 139.8

6 160.0

2 170.0

3 175.0

5 172.4

16 48.0

19 50.0

11 91.9

10 92.8

Price (y )

56.0

99.8

110.0

139.8

160.0

170.0

175.0

172.4

48.0

50.0

91.9

92.8

MA 2113 Homework #6

1. Compute the Pearson correlation coefficient, r, for the data below.

Data from homework #5, age of used Honda Accords (x) and price (y).

To check your final answer, r = – 0.887 X 100 = 88.7%

x y

14 56.0

4 99.8

10 110.0

3 139.8

6 160.0

2 170.0

3 175.0

5 172.4

16 48.0

19 50.0

11 91.9

10 92.8

MA 2113 Homework #7

1. This table contains a distribution of estimated values of NFL teams rounded to the nearest $100

million. Calculate the mean value of NFL teams and the associated standard deviation. (Hint: μ =

1437.5)

Current

Value, x

(mil $)

Freq

(Count)

900 2

1,000 6

1,100 4

1,200 3

1,300 3

1,400 3

1,500 2

1,600 1

1,700 1

1,800 2

1,900 1

2,100 1

2,400 1

2,600 1

3,200 1

MA 2113 Homework #8 Name:_________________________

1. A large species of tarantula, the Brazilian Giant Tawny Red, has 2 body parts, the abdomen and

cephalothorax. The cephalothorax is covered by a shell called the carapace. Carapace length of the

adult male is normally distributed with μ = 18.14 and σ = 1.76.

a) Find the % of adult males that have carapace lengths from 16-19 mm.

b) Find the % of adult males that have carapace lengths >18.5 mm.

c) Find the % of adult males that have carapace lengths <16.5 mm.

d) What is the cut-off length of the top 10% of adult males?

MA 2113 Homework #9 Name:_________________________

From the data set on verbal SAT scores from 728 students, I randomly drew 30 values (on second page).

From the entire population of scores where μ = 456.7 and σ = 83.8.

a) Determine sample mean ( x ) and SD (s) using the 30 random values. You will not use s on this

homework but you will on Homework #10.

b) Calculate a 90% CI using population SD, σ.

c) Calculate a 99% CI using population SD, σ.

d) Does μ fall into your CI?

x

564

512

397

378

395

282

431

298

588

382

421

254

451

402

483

430

489

492

495

355

482

398

404

345

359

534

534

460

448

512

MA 2113 Homework #10 Name:_________________________

1. Construct confidence intervals (CI) from the sample data set from Homework # 9 (verbal SAT scores

from 30 of 728 students) with x = 432.5 and s = 81.9. From the entire population of scores, μ = 456.7

and σ = 83.8.

a) Calculate a 95% CI using sample SD, s.

b) Calculate a 99% CI using sample SD, s.

c) Does μ fall into your CI?

MA 2113 Homework #11 Name:_________________________

We want to compare verbal SAT scores between two schools. From School 1, we have verbal SAT scores

from 728 students (μ = 456.7 and σ = 83.8). For School 2, we don’t have the resources to test all

students, so we randomly test 30 students. We averaged the scores from this sample population for a

sample mean ( x ) = 451.7. We will assume the standard deviation (σ) is the same as the population

standard deviation from School 1.

Using a significance level of 5% (CL = 95%, α = 0.05), are we very confident that the population mean is

the same for both schools? Use the formula for z-test with known σ to make the decision.

ST 2113 Homework #12 Name:_______________________

The Florida State Center for Health Statistics claims that for cardiovascular hospitalizations, the mean

age of women is 71.9 years. At one hospital in Florida, a random sample of 20 of its female

cardiovascular patients had a mean age ( x ) = 72.9 with a sample SD (s) = 13.9.

Using a significance level of 10% (CL = 90%, α = 0.10) and sample SD, are we very confident that the

population mean for this hospital is the same as the state mean?