In 2002, the average duration of incoming telephone calls to a furniture store was 9.4 minutes. The manager wants to perform a test to determine whether this average duration of incoming calls has changed. Twenty calls to the store was randomly selected and the mean duration was 10.2 minutes with standard deviation 4.8 minutes. Assuming that the duration of incoming telephone calls to a furniture store is normally distributed, a) Use a 1% level of significance to test whether the mean duration of incoming calls to the store had changed. b) Construct the 95% confidence interval for the population mean duration of the incoming calls to the furniture store.

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
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In 2002, the average duration of incoming telephone calls to a furniture store was 9.4
minutes. The manager wants to perform a test to determine whether this average duration
of incoming calls has changed. Twenty calls to the store was randomly selected and the
mean duration was 10.2 minutes with standard deviation 4.8 minutes. Assuming that the
duration of incoming telephone calls to a furniture store is normally distributed,
a) Use a 1% level of significance to test whether the mean duration of incoming calls to
the store had changed.
b) Construct the 95% confidence interval for the population mean duration of the
incoming calls to the furniture store.
Transcribed Image Text:In 2002, the average duration of incoming telephone calls to a furniture store was 9.4 minutes. The manager wants to perform a test to determine whether this average duration of incoming calls has changed. Twenty calls to the store was randomly selected and the mean duration was 10.2 minutes with standard deviation 4.8 minutes. Assuming that the duration of incoming telephone calls to a furniture store is normally distributed, a) Use a 1% level of significance to test whether the mean duration of incoming calls to the store had changed. b) Construct the 95% confidence interval for the population mean duration of the incoming calls to the furniture store.
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