ปรีย bathiap is a difference between using an average Independent-Samples T-test statistics before and after the trial. Configure the 95% confidence range of the difference, and if the information is not a normal distribution. ANCOVA statistics used.
Prii comparison of the mean difference between groups by using Independent-Samples T-test before and after the experiment. 95% of the difference. And in case the data is not normal statistical distribution ANCOVA.
Compare the difference between the statistical Independent-Samples T-test before and after the trial, conviction 95% set of differences. And, in the case of normal distribution, with the ANCOVA