# POL242Y5 Lecture Notes - Lecture 11: Dependent And Independent Variables, Statistical Hypothesis Testing, Interquartile Range

## Document Summary

Mode - this is the most frequent value. Median - this is the middle value. Helps tell us the level of variation that exists in our study. For example, we have a mean of 19 and a standard deviation of . 1. With a standard deviation of . 1, there is not a lot of deviation from the age of the mean. However, if the deviation is 10, it shows the variation of age from the mean is large. When we expect that our observation is sensitive to an outlier, we would report the median because this would better reflect the overall results. There is four ways to measure dispersion: Range - subtract highest number from lowest number for the range. Interquartile range - the differences between the 75th percentile (upper quartile) and the 25th percentile (lower quartile). We use range and interquartile range when our variables are interval, or ordinal, not nominal.