Question

suppose you are planning a study anda you would like to have a margin of error +/-0.003 with a 95% confidence level. what sample size should you choose?

Answer 1

Solution :

Given that,

= 0.5

1 - = 1 - 0.5 = 0.5

margin of error = E =+/-0.003

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 ( Using z table )

Sample size = n = (Z/2 / E)2 * * (1 - )

= (1.96 / 0.003 )2 * 0.5 * 0.5

= 106711

Sample size =106711