When testing the difference between two proportions, one sample had 30 out of 100 who were for capital punishment and the other sample had 60 out of 80 who were for capital punishment. Calculate the standard error.
2006-08-11 05:07:46 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
The standard error is the standard deviation of the estimate.
s.e(phat) = sqrt [phat(1-phat)/n]
phat = 30/100 = 0.3
s.e.(phat) = sqrt (0.3 * 0.7 / 100) = sqrt (0.0021)
which is approximately 0.0458
2006-08-11 05:17:58 · answer #1 · answered by Anonymous · 1⤊ 0⤋
You calculate the variance for each sample (see the previous answer Variance=p(1-p)/n), where p is proportion and n is the sample size) let's call them S and V and then calculate the standard error of you test by using
[S/n1 + V/n2]½,
you will have 80 degrees of freedom in your test
2006-08-13 07:07:29 · answer #2 · answered by hec 5 · 0⤊ 0⤋