Question

I am unsure how to solve this problem and what formula

Answer 1

The z-score is gotten as;

`Z=(x-\mu)/((\sigma)/(√(n)))`

Inserting, the values we have;

`Z=(7-8)/((3)/(√(25)))=-1.67`

Thus, using a significance level of 0.05;

Thus, the answer is OPTION C