Question

Suppose Apple claims that the average wait time for a customer calling the Apple Care support line is 175 sec-onds. A random sample of 40 customers had an average wait time of 187 seconds. Assume the population standard deviation for wait time is 50 seconds. Using a 95% confidence interval, does this sample support Apple?

Answer 1

yes

95% confidence intervals for the apple care support

(171.505 ,202.495)

Explanation:

Step(i):-

Given Mean of the Population = 175 seconds

Random sample size 'n' =40

Mean of the sample = 187 seconds

Standard deviation of the Population = 50 seconds

Step(ii):-

95% confidence intervals for the mean is determined by

`(x^(-) - Z_(0.05) (S.D)/(√(n) ) , x^(-) + Z_(0.05) (S.D)/(√(n) ))`

`(187 - 1.96(50)/(√(40) ) , 187 + 1.96 (50)/(√(40) ))`

(187 -15.495 , 187 +15.495)

(171.505 ,202.495)

Final answer:-

95% confidence intervals for the apple care support

(171.505 ,202.495)