Question

14. Claim: The average cost to repair a smart phone is more than $87. Test at α = 0.01. Data: 13 smart phone repairs are chosen at random. The average of these is $85.56, with a standard deviation of $10.
(a) Are these data statistically significant evidence to support the claim?
(b) Are these data statistically significant evidence to refute the claim?

Answer 1

Solution:

This a right (One) tailed test.

The null and alternative hypothesis is,  

Ho: 87

Ha: 87

The test statistics,

t =( - )/ (s /n)

= ( 85.56 - 87 ) / ( 10 / 13 )

= -0.519

P-value = 0.3066

The p-value is p = 0.3066 > 0.01, it is concluded that fail to reject the null hypothesis.

b)

These data statistically significant evidence to refute the claim. at 0.01 significance level.