n= 16 x= 75.607

Ho: >= 80 H_a:< 80

= 8.246

Assume the population is normally distributed.

Refer to Exhibit 9-5. If the test is done at a 2% level of significance, the null hypothesis should _____.

a.not be rejected

b.be rejected

c.be tested again

d.Not enough information is given to answer this question.

The answer is a. But I don't understand why. Please help