SOAN 3120 Lecture Notes - Lecture 5: Standard Score, Sample Size Determination, Central Limit Theorem

• School: University of Guelph
• Department: Sociology and Anthropology
• Course: SOAN 3120
• Professor: Ryan Broll

Document Summary

Hypothesis testing is designed to detect significant differences: differences that did not occur by random chance. Hypothesis testing for single sample means: an example. The e(cid:374)gi(cid:374)ee(cid:396)i(cid:374)g depa(cid:396)t(cid:373)e(cid:374)t at a u(cid:374)i(cid:448)e(cid:396)sity has (cid:271)ee(cid:374) a(cid:272)(cid:272)used of (cid:862)g(cid:396)ade i(cid:374)flatio(cid:374)(cid:863) so engineering majors have much higher gpas than students in general. For a random sample of 117 engineering majors, xbar= 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. However, we are working with a random sample (not all engineering majors: the observed difference may have been caused by random chance. Hence there are 2 explanations, or hypotheses, for the difference: 1. The sample mean (3. 00) is the same as to the pop means (2. 70) the difference is trivial and caused by random chance: 2. The difference is real (significant: engineering majors are different from all students.