But, using the pooled t test, equal variances. One can quibble whether equal variances are part of the null hypothesis. Maybe it is unfair to say that the test has 'detected' unequal variances, but it is clear that unequal variances do change how the test performs. The alternative hypothesis H 12a is that the mean difference The null hypothesis H 02 is that the mean difference (x1-x2) >= 0.8.The null hypothesis H 01 is that the mean difference (x1-x2) 0.8 t-test : Two-sample Assuming Unequal Variances, yaitu t-test yang digunakan untuk menguji perbedaan rata-rata (mean) 2 variabel dari sampel yang berbeda dengan meng-asumsi-kan kedua sampel tersebut memiliki variance yang tidak sama.So, we can eliminate one of the tests.ĭefine the two null and alternate Hypotheses for equivalence: I was recently explaining the WelshSatterthwaite equations application to two sample t-tests of differing variances, but while going through an example using. Now here's where it gets interesting.because the one-tailed p-values are both less than 0.05.
If both p-values are less than 0.05, the means are equivalent. The Equivalence test will perform the calculations and interpret the results for you. QI Macros will prompt for a significance level (default = 0.05 or 0.95):Īlong with the hypothesized mean difference ( Note: this difference will set the range acceptable for equivalence): Bt k bn chn ty chn no trong bc trc, bn s thy cng mt hp thoi nhp chi tit phn tch. Select the data within your Excel spreadsheet, click on QI Macros menu, Statistical Tools and select Equivalence test. Chn tab Data > Data Analysis, sau chn t-Test: Two-Sample Assuming Equal Variances hoc t-Test: Two-Sample Assuming Unequal Variances.
of the two sample variances, with the weights based on the sample sizes.
If they are, one measurement can be eliminated, saving time and money. You could use your sampling distribution of ts to test if the new sample comes. Are the measurements equivalent at these two different points in time. Note: Excel does not do equivalence tests QI Macros adds this functionality.Īdhesive tape is measured immediately after production and 24 hours later.