Question 4 5 points Spin Master Toys is a well established c

Question 4 [5 points]

Spin Master Toys is a well established company with thousands of employees and they want to estimate the average age of their workers. A sample of 31 employees was taken.
Given that the population standard deviation is 12.51 and the sample mean is 41.03, what is the range of values for a 95% confidence interval.

Given below is the formula for computing the confidence interval. Fill in the missing values.
For full marks your answer should be accurate to at least two decimal places.

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Question 4 [5 points] Spin Master Toys is a well established company with thousands of employees and they want to estimate the average age of their workers. A sample of 31 employees was taken. Given that the population standard deviation is 12.51 and the sample mean is 41.03, what is the range of values for a 95% confidence interval. Given below is the formula for computing the confidence interval. Fill in the missing values. For full marks your answer should be accurate to at least two decimal places.

Solution

Given a=1-0.95=0.05, Z(0.025) = 1.96 (from standard normal table)

So the confidence interval is

xbar +/- Z*s/vn

--> 41.03 +/- 1.96*12.51/sqrt(31)

--> 41.03 +/- 4.40385