Question

If σ = 12 then find sample size required to estimate a population mean μ to within 3.6 with 99% confidence?

Answer 1

Solution :

Given that,

standard deviation =s =   =12

Margin of error = E = 3.6

At 99% confidence level the z is,

= 1 - 99%

= 1 - 0.99 = 0.01

/2 = 0.005

Z/2 = 2.58

sample size = n = [Z/2* / E] 2

n = ( 2.58*12 /3.6 )2

n =73.96=74