Question

The mean age of 20 youth volunteers in a community project is 17.5 years with a standard deviation of 2 years. If the sample comes from an approximately normal distribution, what are the point and the interval estimates of the population mean? Use 99% confidence interval level.

Answer 1

Point of estimation is the population mean age $\mu$

$\mu=\overline{x}\pm Z_{0.99}\frac{\sigma}{\sqrt{n}}=17.5\pm 2.576\cdot\frac{2}{\sqrt{20}}=17.5\pm 1.15$

$16.35\le\mu\le18.65$