Practice Questions with Statistics

5. A political polling company wants to know if there are differences among people of different political parties with respect to their views on a bill recently proposed in Congress. The company conducted a survey of 300 people and got the following results. Do the results support the hypothesis that there are differences among people in different political parties regarding their views on this bill? (Use a = 0.10)
Republicans Democrats Independents
Strongly Agree 50 10 20
Agree 20 10 15
Neutral 20 20 10
Disagree 10 35 20
Strongly Disagree 10 30 20

15. A researcher in a private, for-profit university wants to determine whether the average starting salaries differ among recent graduates from their nursing, engineering, business and education programs. He randomly selects graduates from each of these programs and determines their starting salaries (see table below). Is there a significant difference in starting salaries among the four programs? NOTE: values are in $1,000. (Use a = 0.05)

Nursing Engineering Business Education
42 51 60 54
44 49 62 48
47 55 59 49
39 54 61 50
44 58 58 51
46 58
11. A software company wants to know whether the job satisfaction levels of its programmers is linked to their salary levels. The company provides a written questionnaire to a sample of fifteen programmers to measure their job satisfaction levels on a scale of 1 to 10. The data are shown in the table below.
(a) Draw a scatter plot.
(b) Develop a regression equation relating job satisfaction to salary.
(c) Predict the job satisfaction rating for someone with a salary of $30,000.

Job Satisfaction (1-10): 1 2 2 3 3 5 6 6 7 7 8 8 9 9 10
Annual Salary (in $1000): 22 20 23 34 38 24 22 34 36 27 33 27 38 39 40

7. A fast-food company is trying to reduce the amount of time it takes to prepare its Jumbo-Max meal, which takes on average 4.2 minutes ( µ ) and the standard deviation of the population equals 0.8 minutes. The company hires a consultant who designs a new system for preparing the Jumbo-Max and the company uses the new system for a week. During that week, the company makes 64 Jumbo-Max meals and the mean time for the sample is 3.8 minutes. Is the consultant's new system effective in reducing the preparation time? (Use a = 0.01)