Health Sciences 3801A/B Lecture Notes - Lecture 1: Sample Size Determination, Null Hypothesis, Standard Deviation

• School: Western University
• Department: Health Sciences
• Course: Health Sciences 3801A/B
• Professor: Christopher Lee

Document Summary

It is calculated by summing the squared centred scores. It is a short version of the long phrase sum of the square of centred sores. It is equal to zero when all the scores are the same (no variability) It increases up from zero as the scores are more variable it has no maximum upper value: you cannot have negative variability. In a negatively skewed distribution, the upper side is compressed, and the mean is less then the median. In a positive skewed distribution, the lower side is compressed, and the mean is greater than the median: mean often changes more than median. Covariation (relationship: sum of products and simple correlations, sum of products is a measure of covariation (relationship) between two variables. It is calculated by summing the product of centred scores: simple correlation is a (cid:862)sta(cid:374)da(cid:396)dized(cid:863) (cid:448)e(cid:396)sio(cid:374) of the su(cid:373) of p(cid:396)odu(cid:272)ts that (cid:396)a(cid:374)ges f(cid:396)o(cid:373) -