Question

The pulse rates of 159 randomly selected adult males vary from a low of 36 bpm to a high of 108 bpm. Find the minimum sample size required to estimate the mean pulse rate of adult males. Assume that we want 90​% confidence that the sample mean is within 2 bpm of the population mean. Find the sample size using the range rule of thumb to estimate sigma.

Answer 1

We have pulse rate low of 36 bpm to a high of 108 bpm.

Range = Max - min = 108 - 36 = 72

We can estimate standard deviation using range rule of thumb.

  

= 18

Here c = 0.90,

Zc = --------( using excel formula " =norm.s.inv( 0.95) " )

Margin of error = E = 2

Hence the required sample size is,

= 219.19 220

Hence the required sample size is 220.