Question

Consumers Energy states that the average electric bill across the state is $62.138. You want to test the claim that the average bill amount is actually greater than $62.138. The hypotheses for this situation are as follows: Null Hypothesis: μ ≤ 62.138, Alternative Hypothesis: μ > 62.138. A random sample of 28 customer's bills shows an average cost of $61.026 with a standard deviation of $7.3698. What is the test statistic and p-value for this test?

Question 13 options:

1)	Test Statistic: 0.798, P-Value: 0.2158

2)	Test Statistic: -0.798, P-Value: 1.5684

3)	Test Statistic: -0.798, P-Value: 0.2158

4)	Test Statistic: -0.798, P-Value: 0.7842

5)	Test Statistic: 0.798, P-Value: 0.7842

PLEASE make sure your answer is correct, Thank You!

Answer 1

Solution :

This is the right tailed test .

The null and alternative hypothesis is ,

H₀ :   = 62.138

H_a : > 62.138

Test statistic = z

= ( - ) / / n

= (61.026 - 62.138) / 7.3698 / 28

= -0.798

1 - P(z < -.798) = 1 - 0.2158 = 0.7842

P-value = 0.7842