**Unformatted text preview: **Assume n and m to be suﬃciently large . The test statistic for testing H : μ X = μ Y vs. H 1 : μ X 6 = μ Y is Z = ¯ Y-¯ X q S 2 X /n + S 2 Y /m ∼ N (0 , 1) . Example 2. A study was conducted to compare the reaction times of men and women to a stim-ulus. 50 men and 65 women were employed in the experiment. Let X i be the reaction time of the i-th man and Y j be the reaction time of the j-th woman. The following measurements were taken: ¯ x = 3 . 6 seconds, ¯ y = 3 . 8 seconds, s 2 X = 0 . 18, s 2 Y = 0 . 14. Is there any diﬀerence between the reaction times of men and women? > z=(3.6-3.8)/sqrt(0.18/50+0.14/65) > z [1] -2.63664 What is the main reason you are getting the diﬀerent results in Example 1 and 2? Review Problems. Determine the P-values in Ex-ample 1 and 2. Example 9.1., 9.4....

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- Fall '04
- Chung
- Statistics, Variance