Test whether or not there has been a change in the average

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Historically, evening long distance phone calls from a particular city have averaged 15.20 minutes per call. In a random sample of 25 calls, the sample mean time was 14.30 minutes per call, with a sample standard deviation of 2 minutes. Use this sample information to test whether or not there has been a change in the average duration of long distance phone calls. Use a .05 level of significance. What is the p value? 

Reference no: EM13155820

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Test whether or not there has been a change in the average : Use this sample information to test whether or not there has been a change in the average duration of long distance phone calls. Use a .05 level of significance. What is the p value?
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