Question

The Survey of Study Habits and Attitudes (SSHA) is a psychological test that measures the motivation, attitude toward school, and study habits of students. Scores range from 0 to 200, with 200 being the highest level of motivation. The mean score for U.S. college students is about 115, and the standard deviation is about 30. A teacher who suspects that older students have better attitudes toward school gives the SSHA to 20 students who are at least 30 years of age.

a. State the null and alternative hypotheses.

b. The mean of her sample is 116.Calculate the z-statistic.

c. Report the P-value of your test, and state your conclusion clearly: was the teacher justified in her suspicion

ho=115 and h1>115 I have 0.5 left tail test so 6.915 then I get lost.

Answer 1

a) The null and alternative hypothesis is ,

The test is right tailed test.

Since , the population standard deviation is known.

Therefore , use normal distribution .

b) The test statistic is ,

c) The p-value is ,

p-value=

; From standard normal distribution table

d) Decision : Here , p-value=0.4404>0.05

Therefore , fail to reject Ho.

Conclusion : There is not sufficient evidence to conclude that the teacher who suspects that older students have better attitudes toward school gives the SSHA .