Question

A grocer stated that the average grocery bill at his store is $95. A sample of 20 customers' bills showed an average of $97 with a standard deviation of $7.00. You want to test whether the claim is true or not using a=0.05

Answer 1

Solution :

= 95

=97

S =7

n = 20

This is the two tailed test .

The null and alternative hypothesis is ,

H0 :    = 95

Ha :     95

Test statistic = t

= ( - ) / S / n

= (97-95) / 7 / 20

= 1.278

Test statistic = t =1.278  

P-value =0.2167

= 0.05  

P-value >

0.2167 > 0.05

Fail to reject the null hypothesis .

There is insufficient evidence to suggest that