STA 210 Lecture Notes - Lecture 2: Scatter Plot, Gonorrhea
16 Feb 2017
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Document Summary
Correlation: tendency for certain values of one variable to be paired with certain other values of another variable. Correlation in statistics has a more particular meaning. Example: height and weight; taller people are usually heavier people. Scatterplot: a visual way of assessing association, both direction and strength. Most common way to describe the relationship between two variables. Positive association: points have an upward trend from left to right. Negative association: points have a downward trend from left to right. Strength: how tightly points are clustered about some clear pattern. Simple scatterplots are an informal, but useful visual means of addressing both the direction and strength of the relationship between two variables that are appropriate for this kind of plot. Correlation coefficient: a numerical way of summarizing that association between two variables, provides those two can be represented in a scatterplot. The correlation coefficient measures the strength of the linear relationship between two variables x and y .
