A 95% confidence interval for a population mean was reported to be 152 to 160. If = 15, what sample size was used in this study?
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Originally Posted by tonio77 A 95% confidence interval for a population mean was reported to be 152 to 160. If = 15, what sample size was used in this study? Solve the following equations simultaneously for n: $\displaystyle \bar{x} - \frac{1.96\sigma}{\sqrt{n}} = 152$ .... (1) $\displaystyle \bar{x} + \frac{1.96\sigma}{\sqrt{n}} = 160$ .... (1) where $\displaystyle \sigma = 15$.
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