Question

thr heights of FHS male students is normally distributed.
Assume standard deviation of =3.1 inches
How large a sample is necessary to be w/in +/-0.65 inches with a 95% confidence interval.?
use formula:
mean= z* (std deviation)/sq root of n.

what is z*, how do you calculate it and what does it mean please.

Answer 1

Solution:-

Given data:-

Confidence interval = 95%

level of significance = 1-0.95

level of significance = 0.05

At 0.05 level of significance, Z=1.96

standard deviation =3.1 inches

mean= z* (std deviation)/sq root of n

Sample size n = 0.65

'Z' is the critical value at 0.05 level of significance