In: Statistics and Probability
Calculate the sample size needed for a survey study given that
P = 54%, Confidence level is at 99%, acceptable error is 3%
Solution :
Given that,
= 54%=0.54
1 -
= 1 - 0.54= 0.46
margin of error = E = 3% = 0.03
At 99% confidence level the z is,
= 1 - 99%
= 1 - 0.99 = 0.01
/2
= 0.005
Z/2
= 2.58 ( Using z table )
Sample size = n = (Z/2
/ E)2 *
* (1 -
)
= (2.58 / 0.03)2 * 0.54 * 0.46
=1837.1664
Sample size = 1838