Question 6.73

6.73 Hypotheses.

In each of the following situations, state an appropriate null hypothesis and alternative hypothesis . Be sure to identify the parameters that you use to state the hypotheses. (We have not yet learned how to test these hypotheses.)

  1. A sociologist asks a large sample of high school students which academic subject they like best. She suspects that a higher percent of males than of females will name economics as their favorite subject.
  2. An education researcher randomly divides sixth-grade students into two groups for physical education class. He teaches both groups basketball skills, using the same methods of instruction in both classes. He encourages Group A with compliments and other positive behavior but acts cool and neutral toward Group B. He hopes to show that positive teacher attitudes result in a higher mean score on a test of basketball skills than do neutral attitudes.
  3. An economist believes that among employed young adults, there is a positive correlation between income and the percent of disposable income that is saved. To test this, she gathers income and savings data from a sample of employed persons in her city aged 25 to 34.

6.73

(a) = percent of males, = percent of females. . (b) = mean score for Group A, = mean score for group B. . (c) = correlation between income and the percent of disposable income that is saved. .