I ve had and am having the hardest time trying to figure out which hypothesis test to use for the following:
A 2 tailed test
Known: n = # of trials
mean for sample 1
mean for sample 2
n's are <30 AND population variances are NOT known. Since variances are not known, I should use a t-test, but then in order to get Sp^2 I need the variances. Am I trying to use the right test?
Apr 15th 2009, 12:53 AM
Do sample 1 and sample 2 follow any law? n: # of trials seems like it could be a binomial law? In this case you can find the std deviation with the definition of the variation in a binomiale law (mean = E(x) = np; then find var = np(1-p) => std dev = sqrt(var))
If you give the whole question it might be easy to figure out
Apr 15th 2009, 01:00 AM
well, here's the original problem:
An experiment is conducted to determine weather the average dose of vaccine exceeds that of another by .2 mg.
Equal sample sizes, equal variance
This test is only used when both:
the two sample sizes (that is, the n or number of participants of each group) are equal;
it can be assumed that the two distributions have the same variance.