Question

Assuming the population standard deviation = 2.6, at 95% confidence level, how large should a sample be to estimate the population mean with a margin of error not exceeding 0.25? Solve using R.

Answer 1

Margin of error = Critical value x Standard error of the statistic

  

In this context we have

Margin of error =2.5

For 95% confidence interval ,

We want to find n such that margin of error not exceeding 0.25, i.e.

Sample should be at least 416