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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?

Respuesta :

Answer:

yes

95% confidence intervals for the apple care support

(171.505 ,202.495)

Step-by-step 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

[tex](x^{-} - Z_{0.05} \frac{S.D}{\sqrt{n} } , x^{-} + Z_{0.05} \frac{S.D}{\sqrt{n} })[/tex]

[tex](187 - 1.96\frac{50}{\sqrt{40} } , 187 + 1.96 \frac{50}{\sqrt{40} })[/tex]

(187 -15.495 , 187 +15.495)

(171.505 ,202.495)

Final answer:-

95% confidence intervals for the apple care support

(171.505 ,202.495)

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