Let Y1, Y2,..., Yn denote a random sample from a population with mean and variance 2

Stat notes 2 Categorical data= nominal and ordinal Quantitative data= discrete and continuous Relative frequency table- all #’s in table sum to 1 for percentages Proportion= # in category/ total sample size (risk is the same thing as proportion) How do you know which variable is the response and which is the explanatory Rows= response variable Columns= explanatory variable How do we compare the risks of two different groups By using relative risk - If relative risk is less than, first group has a smaller risk - Odds- ratio of counts of the two levels of one categorical variable  haves/have nots Proportion for a sample- p (hat) Proportion for population- P Two-way table- used to show the relationship between two categorical variables Two categorical variables: -