5. The Survey of Study Habits and Attitudes (SSHA) is a psychological test, administered to students, that measures attitude towards school. Scores range from 0 to 200. The mean score for U.S. college students is about 117, and the standard deviation is about 23. A teacher who suspects that older students have better attitudes toward school gives SSHA to 40 students who are at least 30 years of age. Their mean score is x¯ = 133.8.
(a) Assuming that σ = 23 for the population of older students, carry out a test of H0 : µ = 117 Ha : µ > 117 Give the Z test statistic and its P-value.
(b) What do you conclude about older students’ attitudes toward school?
(c) Your test in the previous parts requires assumptions in addition to the assumption that the value of σ is known. What are they?