Sample size based on confidence intervals. The confidence interval for the larger sample is narrower than the interval from Example. For example if you use a confidence interval of 4 and 47 percent of your sample picks an answer you can be sure that if you had asked the question of the entire relevant.
It shifts the point estimate from 026 1350 to 0278 1554.
The basic equation for determining sample size for a two -sided interval when Whas been specified is W UL. Sample size based on confidence intervals. In calculating the sample size we are interested in calculating the population parameter. The standard formula for sample size is.