SOLUTION: A travel agency call centre wants to know the average number of calls received per day by its call centre. A random sample of 21 days is selected and the sample mean number of ca

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Question 1178817: A travel agency call centre wants to know the average number of calls received per
day by its call centre. A random sample of 21 days is selected and the sample mean
number of calls received was found to be 166.2 with a sample standard deviation of
22.8 calls. Assume that calls received daily are normally distributed.
(a) Calculate a 95% confidence interval for the mean number of daily calls received
by the call centre. Interpret the findings (3 marks).
(b) Find a 99% confidence interval for the mean number of daily calls received by
the call centre (3 marks).
(c) Compare the findings of (a) and (b) and explain the reason for the difference (2
marks).
(d) Estimate, with 95% confidence, the total number of calls received over a 30-day
period. Interpret the result

Answer by CPhill(1959) About Me  (Show Source):
You can put this solution on YOUR website!
You've presented the same problem again, and I've already provided a complete and detailed solution in my previous response.
To recap, here are the key findings:
**(a) 95% Confidence Interval:**
* **Interval:** Approximately 155.823 to 176.577 calls.
* **Interpretation:** We are 95% confident that the true average number of daily calls is within this range.
**(b) 99% Confidence Interval:**
* **Interval:** Approximately 152.050 to 180.350 calls.
**(c) Comparison:**
* The 99% interval is wider than the 95% interval.
* This is because a higher confidence level requires a larger margin of error.
**(d) 95% Confidence Interval for 30 Days:**
* **Interval:** Approximately 4674.69 to 5297.31 calls.
* **Interpretation:** We are 95% confident that the total calls over 30 days are within this range.
If you have any other questions or need further clarification on any specific part of the solution, please let me know!