You are interested in estimating the the mean age of the citizens living in your community....

You are interested in estimating the the mean age of the citizens living in your community. In order to do this, you plan on constructing a confidence interval; however, you are not sure how many citizens should be included in the sample. If you want your sample estimate to be within 4 years of the actual mean with a confidence level of 97%, how many citizens should be included in your sample? Assume that the standard deviation of the ages of all the citizens in this community is 25 years.

Sample Size: ______

Solutions

Expert Solution

A % CI for mean can be obtained using the formula:

where, is the margin of Error.

From the above formula, n can be computed as:

Given: and critical value for Z for can be obtained from standard normal table, looking for area :

We get Z_critical = 2.17

Substituting the values:

= 183.9414

We get, Sample size = 184

orchestra answered 1 year ago

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