SSCI 2910U Lecture Notes - Lecture 5: Null Hypothesis, Standard Score, Statistical Hypothesis Testing
31 Mar 2018
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Week 8 lecture 5- hypothesis testing i: the one-sample case. Hypothesis testing: hypothesis testing is designed to detect significant differences, we (cid:449)ill fo(cid:272)us o(cid:374) the (cid:862)o(cid:374)e-sa(cid:373)ple(cid:863) (cid:272)ase: (cid:449)e (cid:272)o(cid:373)pa(cid:396)e a (cid:396)a(cid:374)do(cid:373) sa(cid:373)ple (from a large group) against a population. There are 1000s of engineering majors, far too many to interview. How can the dispute be investigated without interviewing all engineering majors: for a random sample of 117 engineering majors, = 3. 00: there is a difference between the parameter (2. 70) and the statistic (3. 00). It seems that engineering majors do have higher gpas: the sample mean (3. 00) is the same as the pop. mean (2. 70), the difference is real (significant). Engineering majors are different from all students: formally, we can state the two hypotheses as: Null hypothesis (h0) = (cid:862)the diffe(cid:396)e(cid:374)(cid:272)e is (cid:272)aused (cid:271)y (cid:396)a(cid:374)do(cid:373) (cid:272)ha(cid:374)(cid:272)e. (cid:863) Alternative hypothesis (h1) = (cid:862)the diffe(cid:396)e(cid:374)(cid:272)e is (cid:396)eal(cid:863) Always contradicts h0: one (and only one) of these explanations must be true.
