# PSYB01H3 Chapter Notes - Chapter 12: Observational Error, Binomial Distribution, Sampling Distribution

## Document Summary

Two reasons for statistics: statistics are used to describe data, used to make inferences on data. Variable must have operational definition + have 2/more levels of variable . Levels of variables can be described using four scales: nominal, ordinal, interval, ratio. Scale used determines types of statistics that appropriate when results of study are analyzed . Level of nominal scale variable: have no numerical, quantitative properties . Levels are simply different categories / groups . Variable with ordinal scale level: minimal quantitative distinctions . Rank order level of variable from lowest to highest . Internal and ration scale variable: more detailed quantitative properties. Internal scale variable: intervals between level are equal in size . No absolute zero point, no absence of mood . Ratio scale variable: equal interval, have absolute zero points . Three ways in describing results: comparing group percentage: