Question

How large of a sample size is needed to ensure that a fuel estimate has a martin of error that is no more than 5 units, with 95% confidence and a known population standard deviation of 7units ?

Also what is your alpha value / z score / standard deviation and margin of error?

Answer 1

Given that, margin of error (E) = 5 units

population standard deviation = 7 units

confidence level = 0.95

=> significance level = 1 - 0.95 = 0.05

A 95% confidence level has significance level of 0.05 and critical value is,

We want to find, the sample size (n),

=> n ≈ 8

Therefore, required sample size is 8