STAT 3025Q Chapter Notes - Chapter 9: Test Statistic, Type I And Type Ii Errors, Null Hypothesis
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18 Dec 2017
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9. 1 z tests and confidence intervals for a difference between two population means between the means of two different population. Concerns a difference (cid:541)1 (cid:541)2 distributions. 2 n is a random sample from a distribution with mean is a random sample from a distribution with mean. X and y samples are independent of one another. X y is (cid:541)1 (cid:541)2 (cid:541)1 (cid:541)2 and variance and variance. Sample variances can be used to estimate when. Test procedures for normal populations with known variances. Case i both population distributions are normal and. Null hypothesis h0 (cid:541)1 (cid:541)2 = 0. Ha (cid:541)1 (cid:541)2 < 0 z z (upper tailed test) z z (lower tailed test) Observational study - when individuals or objects to be used in the comparison are not assigned by the investigators to the two different conditions. Randomized controlled experiment - investigators assign subjects to the treatments in a random fashion. 2 are known, where (t ype ii error when (cid:541)