Question

The sample size needed to provide a margin of error of 4 or less with a 0.95 probability when the population standard deviation equals 10 is

Group of answer choices

111

30

140

25

Answer 1

Margin of error formula is =

Here population standard deviation, = 10

Also probability = 0.95 given mean for 95 % confidence and for 95% confidence z = 1.960

We have to calculate n for

Margin of error 4

So,

  

  

  

  

so n, sample size= 25

Option (d) 25 is correct.