We are formulating a 90% confidence interval for the population mean and would like our confidence interval to have a margin of error that is not larger than 3. Experience suggests that a reasonable estimate for the population standard deviation is 15. What minimum sample size should be anticipate using? (NOTE: Round your final answer up to the next whole number).

A sample size of 68 should be anticipated using.

Step-by-step explanation:

We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of .

That is z with a pvalue of , so Z = 1.645.

Now, find the margin of error M as such

In which is the standard deviation of the population and n is the size of the sample.

Experience suggests that a reasonable estimate for the population standard deviation is 15

This means that

What minimum sample size should be anticipate using?

Margin of error at most 3, which means that the sample size is n when M = 3. So

Simplifying both sides by 3:

Rounding up

A sample size of 68 should be anticipated using.

step-by-step explanation:

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