Some questions in Part A necessitate the use of data from Statistics for People Who (Think) Hate Statistics. This information is accessible via the Student Text Resources link on the student website.

1. Test the research hypothesis at the using the data in the file named Ch. 11 Data Set 2.

Boys raise their hands in class more frequently than girls, according to a 05 level of significance. Use a calculator to solve this practice problem by hand. What is your opinion on the research hypothesis? Remember to decide whether this is a one-tailed or two-tailed test first.

2. Using the same data set (Ch. 11 Data Set 2), test the research hypothesis that there is a difference in the number of times boys and girls raise their hands in class at the.01 level of significance. Use a calculator to solve this practice problem by hand. What is your opinion on the research hypothesis? You used the same data for this problem as you did for Question 1, but your hypothesis is different (one is directional and the other is nondirectional). How and why do the outcomes differ?

3. Try the following problems by hand to see if you can get the numbers correct. Calculate the t test statistic using the following data.

a.

b.

c.

4. Given the results from Question 3 and a level of significance of.05, what are the two-tailed critical values for each? Is the null hypothesis going to be rejected?

5. Using the data from Ch. 11 Data Set 3, test the null hypothesis that urban and rural residents have the same attitude toward gun control. To complete the analysis for this problem, use IBM® SPSS® software.

6. A public health researcher tested the hypothesis that providing child safety seats to new car buyers would also act as an incentive for parents to take other precautions to protect their children (such as driving more safely, child-proofing the home, and so on). Dr. L recorded all instances of safe behavior in the cars and homes of parents who accepted the seats versus those who did not. The results showed a significant difference at the.013 level. Another researcher conducted the exact same study; everything was identical—the same type of sample, the same outcome measures, the same car seats, and so on. Dr. R’s findings were marginally significant at the.051 level (recall Ch. 9). Which outcome do you believe more, and why?

7. Indicate whether you would perform a t test of independent or dependent means in the following examples.

a. For ankle sprains, two groups were randomly assigned to different treatment levels. Which treatment proved to be the most effective?

b. A nursing researcher wanted to know if patients recovered faster when they received more in-home care than when they received the standard amount.

c. A group of adolescent boys was given interpersonal skills training and then tested in September and May to see if it had any effect on family harmony.

d. One group of adult men was given instructions on how to reduce their high blood pressure, while another group received no instructions.

e. One group of men was given access to an exercise program and had their heart health tested twice over a 6-month period.

8. For Ch. 12 Data Set 3, compute the t value and write a conclusion on whether there is a difference in satisfaction level in a group of families’ use of service centers following a social service intervention on a scale of 1 to 15 on a scale of 1 to 15. Use IBM® SPSS® software to complete this exercise and report the exact probability of the outcome.

9. Carry out this exercise by hand. A well-known brand wants to know whether people prefer Nibbles or Wribbles. They try each type of cracker and rate it from 1 to 10 on a scale of 1 to 10. Which one do they prefer?