# Statistics Problem About Sample Size

3. The equation for determining necessary sample size (n) for confidence intervals about the mean is:

n = [z · s / E]2

Remember that the z-score corresponds to the level of confidence (if confidence is higher, the z-score is higher).

a. If we double our confidence level, what happens (numerically) to the sample size?

b. If we cut our margin of error (E) in half, what happens (numerically) to the sample size?

c. What size sample would you need to have 0 margin of error (i.e. E = 0)?

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a. If we double our confidence level, what happens (numerically) to the sample size?

Solution: Note that if confidence is higher, the z-score is higher. So, if we double our ...

#### Solution Summary

This solution provides assistance with statistics problems such as finding sample size based on the confidence level and margin of error.