1 The Metro City Bus system is concerned about the number of people who complain about the service. Metro City Bus managers suspect that many people do not know how to complain. Last year complaints averaged 47.3 per day. This year, bus systems manager Ralph Kramden has posted a sign in all buses listing a number to call with complaints. Ralph would like to know whether this effort has generated any additional complaints. He takes a sample of 50 days and finds a mean of 54.7 and a standard deviation of 25.4. What can you tell Ralph?
2
The department at BuffordStateUniversity publish an average of 15.1 professional articles a year. The sociology department regularly averages about 3.5. The chairman of the sociology department, Steig Willick, feels her department does less well because it is harder to publish in sociology. Willick takes a survey of 12 other departments and finds the following: X=4.2 s=1.6
What can Willick tell the dean?
Estimating Population Proportions
3
Last year, 30% of all students at WheezerSchool missed class during March because of illness. This year, the school board requires all teachers to dispense vitamin c tablets during the morning milk break. A sample of 60 children reveals that only 12 missed school during March. What can be said about the difference in absentee rates?
Testing the Difference between Two Groups
4
The manager of the Houston Astros decides to see whether batting practice has any impact on the Astros' hitting. Twenty Astros take batting practice; they are randomly selected. Ten Astros, randomly selected, take no batting practice (the control group). After 25 games, the figures shown in the accompanying table are available. What can you tell the manager about his experiment, statistically and managerially?
5.
General Kleinherbst is concerned with the VD (venereal disease) epidemic among soldiers in Europe. At a non-routine inspection of 100 troops, 31 were found to have VD. Kleinherbst requires all troops to view the award-winning film VD: Just between Friends. At another inspection 180 days later, Kleinherbst finds that 43 of the 200 troops inspected have VD. What can you say about the program statistically, managerially, and from a research design point of view?