Question

Find the minimum sample size n needed to estimate

muμ

for the given values of​ c,

sigmaσ​,

and E.

cequals=0.95

sigmaσequals=8.2

and

Eequals=1

Assume that a preliminary sample has at least 30 members.

Answer 1

Solution

standard deviation = =8.2

Margin of error = E = 1

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z/2 = Z0.025 = 1.96

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

n = ( 1.96* 8.2 / 1 )2

n =258.309

Sample size = n =259