What if the first sample size is less than 30 and the other is greater than 30??
If I understand your question, then you have two samples from a same population. If they have been obtained from an accepted sampling protocol (random based), then you can calculate a confidence interval for each sample mean by calculating the variance, standard deviation, and standard Error (s/sqrt(n)). Then you will have to determine a value for your probability value (0.05). If n > 30 you can use the Z (normal) distribution probabilities (two-tailed) table (or formula). For n < 30, ("small" sample size) it is more appropriate to use the tabulated values of a t-student (two-tailed, n-1 degrees of freedom). As when n > 30, the values for the Student-t are pretty close to those of the Normal distribution, you can use a the t value as well for n > 30. The calculation of the confidence intervals around each sample mean is then straightforward.
Regards
Yes.. thanks but I got my answer.. I think the link which I'm posting below is the appropriate answer to my question
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