Question

Assume that all​ grade-point averages are to be standardized on a scale between 0 and 4. How many​ grade-point averages must be obtained so that the sample mean is within 0.008 of the population​ mean? Assume that a 95​% confidence level is desired. If using the range rule of​ thumb, sigma can be estimated as StartFraction range Over 4 EndFraction equalsStartFraction 4 minus 0 Over 4 EndFraction equals1. Does the sample size seem​ practical?

Answer 1

Answer

By range rule of thumb

sigma = range/4

= 4/4

= 1

Given that

margin of error(E)= 0.008

sigma = 1

z critical = 1.96

sammple size n= ((z*sigma)/E)^2

=((1.96*1)/0.008)^2

= 245^2

= 60025

No, sample size dont seem practical because sampling a total of 60025 people is too time consuming process