Chapter 6.9, Problem 4E

The following table illustrates the BMI for a number of patients recently enrolled in a study investigating the relationship between BMI and type 2 diabetes. Participant BMI (kg/m2) A  26.5 B  19.2 C  29.7 D  27.4 E  30.2 F  28.9 A) Assuming the participants can be considered to be normally distributed, and that they come from a population with a σ=2.4 kg/m , calculate a 95% confidence interval for the mean BMI of the population for which they represent and correctly interpret the confidence interval you found.

For a sample of 400 correctional officers at Lucasville State Prison, a researcher believes there is a relationship between “years on the job” and “willingness to help raise money for adult charities.” Using the following data, test the null hypothesis at the .01 level of significance that willingness to help raise donations does not differ by length of service as a correctional officer.  In so doing, identify: (1) the research and null hypothesis, (2) the critical value needed to reject the null, (3) the decision that you made upon analyzing the data, and (4) the conclusion you have drawn based on the decision you have made.

A 30 month study is conducted to determine the difference in rates of accidents per month between two departments in an assembly plant. If a sample of 12 from the first department averaged 12.3 accidents per month with a standard deviation of 3.5, and a sample of 9 from the second department averaged 7.6 accidents per month with standard deviation of 3.4, find: The t-value for a 95% confidence interval is:   A. 2.09302 B. 1.724718 C. 2.08596 D. 1.729133 E. none of the preceding