Question

Assume that females have pulse rates that are normally distributed with a mean of mu equals 72.0 beats per minute and a standard deviation of sigma equals 12.5 beats per minute.

If 25 adult females are randomly​ selected, find the probability that they have pulse rates with a mean between 68 beats per minute and 76 beats per minute.

Answer 1

mean is 72 and sd is 12.5

standard error is 12.5/sqrt(25)=2.5

P(68<x<76)= P((68-72)/2.5<z<(76-72)/2.5)=P(-1.6<z<1.6) or 2*P(z<1.6)-1

from normal distribution table we get 2*0.9452-1=0.8904