Midterm questions

02 Sep Midterm questions

1. A recent study of 33 Jackson County, Missouri residents revealed that they had lived at their current address for a mean of 10.7 years, with a sample standard deviation of 3 years.

a. What is the population mean?

b. What is the best estimate of the population mean?

c. What is the standard error of the mean?

d. Develop a 90% confidence interval for the population mean.

Chapter 10

2. The park manager at Fort Fisher State Park in North Carolina believes that the typical park visitor spends at least 90 minutes in the park during the summer months. A sample of 18 visitors during the summer months of 2011 revealed the mean in the park was 96 minutes with a standard deviation of 12 minutes. At the 0.01 significance level, is it reasonable to conclude that the mean time in the park is greater than 90 minutes?

Chapter 11

3. Dial Soap Company developed a new soap for men and test marketed the product in two cities. The sample information is reported below. At the 0.05 significance level, can we conclude there is a difference in the proportion that liked the new soap in the two cities?

City	Liked New Soap	Number Sampled
Erie, PA	128	300
Tustin, CA	149	400

Chapter 12

4. The results of a one-way ANOVA are reported below.

Source of variation	SS	df	MS	F
Between groups	6.90	2	3.45	5.15
Within groups	12.04	18	0.67
Total	19.34	20

a. How many treatments are there in the study?

b. What is the total sample size?

c. What is the critical value of F?

d. Write out the null hypothesis and the alternate hypothesis?

e. What is your decision regarding the null hypothesis?

f. Can we conclude any of the treatment means differ?

Chapter 13

5. At the end of each calendar year, employees of the G. G. Green Manufacturing Company can purchase company stock. For a sample of employees, the Director of Human Resources investigated the relationship between the number of years of service with the company and the number of shares of company stock owned. The “number of years of service” is used to estimate the “number of shares of stock”. Use the following output showing the results of the analysis to answer the questions.

ANOVA Table

Source	SS	df	MS	F
Regression	152,399.0211	1	152,399.0211	62.67
Residual	55,934.1189	23	2,431.9182
Total	208,333.1400	24

Regression Output

Variables	Coefficients	Std. Error	T (df = 23)
Intercept	197.9229	34.3047	5.770
Years	24.9145	3.1473	7.916

a. How many employees were included in the study?

b. Is “number of shares of stock” or “number of years of service” the dependent variable?

c. Write out the regression equation.

d. Is the relationship between the two variables direct or indirect?

e. Determine the correlation coefficient.

f. How many shares would you expect an employee of 10 years to own?

g. For each additional years of service, how much does “number of shares owned” change?

h. Can we conclude that as years of service increases, so do the number of shares of stock owned? Conduct an appropriate test of hypothesis on the slope of the regression line.