A Single Population Mean Using the Normal Distribution · Example 4

Leave everything the same except the sample size. Use the original 90 percent confidence level. What happens to the error bound and the confidence interval if we increase the sample size and use n = 100 instead of n = 36? What happens if we decrease the sample size to n = 25 instead of n = 36?

• $\bar{x}$ = 68
• EBM = $\left(z_{\frac{\alpha }{2}}\right)\left(\frac{\sigma }{\sqrt{n}}\right)$
• σ = 3, the confidence level is 90 percent (CL = 0.90), $z_{\frac{\alpha }{2}}$ = z_0.05 = 1.645.

OpenStax, Statistics · §8.1 A Single Population Mean Using the Normal Distribution · Example 4