8. In comparing the two variances below, what is the test value and what are the degrees of freedom that should be used?
Variance Number of values
Sample 1 7 12
Sample 2 10 26
10. A college class believes that the average grade average of psychology students and the average grade averages of biology students are different. The class found that the actual grade averages of a sample of 11 psychology students was 3.5 and the average grade average of a sample of 14 biology students was 3.3. What is the null hypothesis for this study?
12. 68% of students at a university live on campus. A random sample found that 25 of 45 male students and 39 of 50 of female students lived on campus. At the .05 level of significance, is there sufficient evidence to conclude that a difference exists between the proportion of male students who live on campus and the proportion of female students who live on campus?
13. In comparing the two standard deviations below, what is the test value and what are the degrees of freedom that should be used?
Standard Deviation Number of values
Sample 1 6 18
Sample 2 3 23
14. One poll found that 46% of male voters will support a candidate while another found that 49% of female voters will be in support. To test whether this candidate has equal levels of support between male and female voters, what should the alternative hypothesis be?
15. A study of cats and dogs found that 22 of 40 cats and 37 of 55 dogs slept more than 10 hours per day. At the .05 level of significance, is there sufficient evidence to conclude that a difference exists between the proportion of cats and the proportion of dogs that sleep more than 10 hours per day?
17. A researcher hypothesizes that the variation in the car rental rates at a major cities' airport is less than the car rental rates in that city. The variance of 9 airport car rental rates was $30 and the variance of 5 city car rental rates was $60. What is the test value?
19. A medical researcher is interested in whether patients' left arms or right arms are longer. If 8 patients participate in this study (so that n left arms and n left arms are measured), how many degrees of freedom should the researcher use in her t-test critical value?