The ages of MBA students at a university are normally distributed with a known population variance of 10.24. Suppose you are asked to construct a 95% confidence interval for the population mean age if the mean of a sample of 36 students is 26.5 years. What is the margin of error for a 95% confidence interval for the population mean

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Answer:

The margin of error for a 95% confidence interval for the population mean is of 1.05 years.

Step-by-step explanation:

We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:

[tex]\alpha = \frac{1-0.95}{2} = 0.025[/tex]

Now, we have to find z in the Ztable as such z has a pvalue of [tex]1-\alpha[/tex].

So it is z with a pvalue of [tex]1-0.025 = 0.975[/tex], so [tex]z = 1.96[/tex]

Now, find the margin of error M as such

[tex]M = z*\frac{\sigma}{\sqrt{n}}[/tex]

In which [tex]\sigma[/tex] is the standard deviation of the population(square root of the variance) and n is the size of the sample.

What is the margin of error for a 95% confidence interval for the population mean

36 students, so [tex]n = 36[/tex]

Variance of 10.24, so [tex]\sigma = \sqrt{10.24} = 3.2[/tex]

[tex]M = 1.96*\frac{3.2}{\sqrt{36}} = 1.05[/tex]

The margin of error for a 95% confidence interval for the population mean is of 1.05 years.

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