5. Recreational time A researcher wants to see if there is a difference between the average number of hours per week that a family without children participates in recreational activities and a family with children participates in recreational activities.She selects two random samples and the data is displayed.At a = 0.10, is there a difference between the means?Without children 8.6 2.1 36 Children 10.6 2.7 36

6. Teachers 'Salaries Teachers' Salaries New York and Massachusetts lead the list of average teacher's salaries.The New York average is $ 76,409 while teachers in Massachusetts make an average annual salary of S73,195.Random samples of 45 teachers from each state yielded the following.Massachusetts New York Sample means S73,195 S76,409 Population standard deviation 8,200 7,800 Page 495 At a = 0.10, is there a difference in means of the salaries?

8. Heights of 9-Year-Olds At age 9 the average weight (21.3 kg) and the average height (124.5 cm) for both boys and girls are exactly the same.A random sample of 9-year-olds yielded these results.At a = 0.05, do the data support the given claim that there is a difference in heights?Boys Girls Sample size 60 50 Mean height, cm 123.5 126.2 Population variance 98 120 Source: www.healthepic.com

14. Monthly Social Security Benefits The average monthly Social Security benefit for a specific year for retired workers was $ 954.90 and for disabled workers was $ 894.10.Researchers used data from the Social Security records to test the claim that the difference in monthly benefits between the two groups was greater than $ 30.Based on the following information, can the researchers' claim be supported at the 0.05 level of significance?Retired Disabled Sample size 60 60 Mean benefit $ 960.50 $ 902.89 Population standard deviation $ 98 $ 101 Source: New York Times Almanac.

16. Ages of College Students The dean of students wants to see whether there is a significant difference in ages of resident students and commuting students.She selects a random sample of 50 students from each group.The ages are shown here.At a = 0.05, decide if there is enough evidence to reject the claim of no difference in the ages of the two groups.Use the P-value method.Assume o, - 3.68 and o, = 4.7.Resident students |22 25 27 23 26 28 26 24 25 20 26 24 27 26 18 19 18 30 26 18 18 19 32 23 19 19 18 29 19 22 18 22 26 19 19 21 23 18 20 18 22 21 19 21 21 22 18 20 19 23