Buy here: http://homework.plus/math-302-statistics-quiz-3/ 1. Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-),

spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated

values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

Senior management of a consulting services firm is concerned about a growing decline in the

firm’s weekly number of billable hours. The firm expects each professional employee to spend at

least 40 hours per week on work. In an effort to understand this problem better, management

would like to estimate the standard deviation of the number of hours their employees spend on

work-related activities in a typical week. Rather than reviewing the records of all the firm’s

full-time employees, the management randomly selected a sample of size 51 from the available

frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively.

Construct a 99% confidence interval for the standard deviation of the number of hours this firm’s

employees spend on work-related activities in a typical week

2. Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-),

spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated

values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

Senior management of a consulting services firm is concerned about a growing decline in the

firm’s weekly number of billable hours. The firm expects each professional employee to spend at

least 40 hours per week on work. In an effort to understand this problem better, management

would like to estimate the standard deviation of the number of hours their employees spend on

work-related activities in a typical week. Rather than reviewing the records of all the firm’s

full-time employees, the management randomly selected a sample of size 51 from the available

frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively.

Construct a 90% confidence interval for the standard deviation of the number of hours this firm’s

employees spend on work-related activities in a typical week

3. Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-),

spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated

values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

Senior management of a consulting services firm is concerned about a growing decline in the

firm’s weekly number of billable hours. The firm expects each professional employee to spend at

least 40 hours per week on work. In an effort to understand this problem better, management

would like to estimate the standard deviation of the number of hours their employees spend on

work-related activities in a typical week. Rather than reviewing the records of all the firm’s

full-time employees, the management randomly selected a sample of size 51 from the available

frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively.

Construct a 90% confidence interval for the standard deviation of the number of hours this firm’s

employees spend on work-related activities in a typical week

4. Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-),

spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated

values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

After calculating the sample size needed to estimate a population proportion to within 0.05, you

have been told that the maximum allowable error (E) must be reduced to just 0.025. If the original

calculation led to a sample size of 1000, the sample size will now have to be . Place your

answer, as a whole number in the blank. For example, 2345 would be a legitimate entry

5. Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-),

spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated

values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

Senior management of a consulting services firm is concerned about a growing decline in the

firm’s weekly number of billable hours. The firm expects each professional employee to spend at

least 40 hours per week on work. In an effort to understand this problem better, management

would like to estimate the standard deviation of the number of hours their employees spend on

work-related activities in a typical week. Rather than reviewing the records of all the firm’s

full-time employees, the management randomly selected a sample of size 51 from the available

frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively.

Construct a 95% confidence interval for the standard deviation of the number of hours this firm’s

employees spend on work-related activities in a typical week

6. Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-),

spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated

values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

The personnel department of a large corporation wants to estimate the family dental expenses of

its employees to determine the feasibility of providing a dental insurance plan. A random sample

of 12 employees reveals the following family dental expenses (in dollars): 115, 370, 250, 593,

540, 225, 177, 425, 318, 182, 275, and 228.

Construct a 99% confidence interval estimate for the standard deviation of family dental

expenses for all employees of this corporation.

Place your LOWER limit, in dollars rounded to 1 decimal place, in the first blank. Do not use a

dollar sign, a comma, or any other stray mark. For example, 98.4 would be a legitimate entry

7. Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-),

spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For

scientific notation, a period MUST be used as the decimal point marker.

Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated

values.

For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not.

A sample of 40 country CD recordings of Willie Nelson has been examined. The average playing

time of these recordings is 51.3 minutes, and the standard deviation is s = 5.8 minutes.

Using an appropriate t-multiplier, construct a 95% confidence interval for the mean playing time

of all Willie Nelson recordings.

Place your LOWER limit, in minutes, rounded to 2 decimal places, in the first blank. For example,

56.78 would be a legitimate entry

8. A food snack manufacturer samples 15 bags of pretzels off the assembly line and weighed

their contents. If the sample mean is 10.0 and the sample standard deviation is 0.15, find the

95% confidence interval estimate for the true mean

9. If you increase the confidence level, the confidence interval ____________.

10. When you calculate the sample size for a proportion, you use an estimate for the population

proportion; namely . A conservative value for n can be obtained by using

11. The average gas mileage of a certain model car is 26 miles per gallon. If the gas mileages

are normally distributed with a standard deviation of 1.3, find the probability that a randomly

selected car of this model has a gas mileage between 25.8 and 26.3 miles per gallon

12. At a large department store, the average number of years of employment for a cashier is 5.7

with a standard deviation of 1.8 years. If the number of years of employment at this department

store is normally distributed, what is the probability that a cashier selected at random has worked

at the store for over 10 years?

13. In order to be accepted into a top university, applicants must score within the top 5% on the

SAT exam. Given that SAT test scores are normally distributed with a mean of 1000 and a

standard deviation of 200, what is the lowest possible score a student needs to qualify for

acceptance into the university?

14. Find the 95% confidence interval for the standard deviation of the lengths of pipes if a sample

of 26 pipes has a standard deviation of 10 inches

15. Confidence intervals are a function of which of the following three things?

16. The t- distribution for developing a confidence interval for a mean has _____ degrees of

freedom

17. A sample of 23 European countries found that the variance of life expectancy was 7.3 years.

What is the 95% confidence interval estimate for the variance of life expectancy in Europe?

18. Compute where t20 has a t-distribution with 20 degrees of freedom.

19. As a general rule, the normal distribution is used to approximate the sampling distribution of

the sample proportion, , only if the sample size n is greater than 30

20. The lower limit of the 95% confidence interval for the population proportion p, given that n =

300; and = 0.10 is 0.1339