power function non-pooled t-test

Hi,

I try to plot the power function of a non-pooled t-test.

Is there a chance to modify sampsizepwr to get a non-pooled t2-test instead of a pooled one?

Answer 1

[Saket Chirania]

Hi Lena,

We can use the samsizepwr command for the respective testtypes:

• 'z' — z-test for normally distributed data with known standard deviation.

• 't' — t-test for normally distributed data with unknown standard deviation.

• 't2' — Two-sample pooled t-test for normally distributed data with unknown standard deviation and equal variances.

• 'var' — Chi-square test of variance for normally distributed data.

• 'p' — Test of the p parameter (success probability) for a binomial distribution. The 'p' test is a discrete test for which increasing the sample size does not always increase the power. For n values larger than 200, there may exist values smaller than the returned n value that also produce the specified power.

For more information you can refer the link - Sample size and power of test