STAT231 Lecture Notes - Lecture 3: Relative Risk, Normal Distribution, If And Only If

• School: University of Waterloo
• Department: Statistics
• Course: STAT231
• Professor: Surya Banerjee

Document Summary

Practice problems with solutions on learn, <= wednesday"s class for the tq1 next week. Today: measures of symmetry, measures of kurtosis, applications, measures of association, graphical measures. Symmetric data -> mean = median e. g. 1, 3, 5, 7, 9, 11, 107 mean median. Measure of skewness = mean - median if > 0, right-skewed, mean greater than median if < 0, left-skewed, mean less than median if = 0, symmetric. Abdominal mesothalamia : median of life expectancy after diagnosis = 8 months. If the distribution (of frequency of death against time since diagnosis) is symmetric, then he will die within 16 months at best. Kurtosis measure how frequent extreme observations are, with respect to the normal. Kurtosis checks whether the data set has fatter tails compared to the normal distribution. If k for your data > 3, then it has fatter tails compared to the normal. If it is < 3, then it has narrower tails.