Question

Suppose you want to estimate the mean diameter of a lunar crater to within 1.5 mi. A confidence level of 99% is desired. Assume standard deviation = 5.7 mi. How many craters must be sampled?

Answer 1

Solution :

Given that,

standard deviation =   =5.7

Margin of error = E = 1.5

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*5.7 / 1.5 )2

n =96.1184

Sample size = n =97