In: Statistics and Probability
A college believes that 22% of aoolication to that school have parents who have remarried. How large a sample is needed to estimate the true poroportion of students who have parents who have remarried to within 3% with 95% confidence.
Solution :
Given that,
= 22% = 0.22
1 - = 1 - 0.22 = 0.78
Margin of error = E = 3% = 0.03
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 = ( Z/2 / E)2 * * (1 - )
= (1.96 / 0.03)2 * 0.22 * 0.78
= 732.46 = 733
Sample size = n = 733