2. Write a short paragraph explaining what is wrong in each situation and why it

Question

2. Write a short paragraph explaining what is wrong in each situation and why it is wrong.

(a) A significance test rejected the null hypothesis that the sample mean is equal to 500.

(b) A test preparation company wants to test that the average score of their students on the ACT is better than the national average score of 21.2. They state their null hypothesis to be Ho: >21.2 .

(c) A study summary says that the results are statistically significant and the P-value is 0.98.

(d) The z test statistic is equal to 0.018. Because this is less than =0.05, the null hypothesis was rejected.

Explanation / Answer

(a) The null hypothesis has the population mean in it. It cannot have the sample mean. (H0: = 500)

(b) The Null Hypothesis should always contain the '=' sign. Therefore Null hypothesis should have been H0: = 21.2 and the alternate Hypothesis H1: > 21.2.

(c) A test is statistically significant if my p value is < . The value of commonly used are 0.2,0.1,0.05,0.01. Therefore in all these case p value is > , and the tests will never be statistically significant.

(d) The null hypothesis if (a) the P value is < . not if the test statistic is <

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.