Computes the sample size required to estimate a population mean with
desired confidence interval precision. Set the variance planning value to
the largest value within a plausible range for a conservatively large
sample size.
Usage
size.ci.mean(alpha, var, w)
Arguments
- alpha
alpha level for 1-alpha confidence
- var
planning value of response variable variance
- w
desired confidence interval width
Value
Returns the required sample size
Examples
size.ci.mean(.05, 264.4, 10)
#> Sample size
#> 43
# Should return:
# Sample size
# 43