Please assist with question 4 and kindly show all workings. Thank you! In 2015, the average duration of long-distance telephone calls from a certain town was 3.9 minutes. A telephone company wants to perform a test to determine whether this average duration of long- distance calls has changed. Fifty calls, originating from the town, was randomly selected and the following summary minutes. ∑ ? = 205 ∑(? − ?̅)2 = 56.43 Calculate the sample mean, ?̅. Calculate the sample standard deviation 3. Using the p value approach at the 1% level of significance, test whether the mean duration of long-distance calls from the town had increased. 4. Construct the 99% confidence interval for the population mean duration of the long-distance calls from the town.
Please assist with question 4 and kindly show all workings. Thank you!
In 2015, the average duration of long-distance telephone calls from a certain town was 3.9 minutes. A telephone company wants to perform a test to determine whether this average duration of long- distance calls has changed. Fifty calls, originating from the town, was randomly selected and the following summary minutes.
∑ ? = 205 ∑(? − ?̅)2 = 56.43
- Calculate the sample
mean , ?̅. - Calculate the sample standard deviation
3. Using the p value approach at the 1% level of significance, test whether the mean duration of long-distance calls from the town had increased.
4. Construct the 99% confidence interval for the population mean duration of the long-distance calls from the town.
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