STAT 101 Lecture Notes - Lecture 4: Dependent And Independent Variables, Scatter Plot
10 Oct 2015
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Response(dependent) variable(y): measures an outcome of a study. Explanatory(independent/predictor) variable(x): explain or influence changes in a response variable. Scatterplot: graph that displays the relationship between two quantitative variables measured on the same individuals. Describe the overall pattern of the plot by its direction, form, ands strength. Direction: move from lower left to upper right/upper right to lower left/neither (use association and relationship to describe: positively associated: one variable increase, another also increase, negatively associated: one increase, another decrease. Strength: how closely the points in the plot follow the form. i. e. if they fall almost perfectly on a straight line, it"s a close relationship. If they are widely scattered around a straight line, the relationship is weak. To add a categorical variable to a scatterplot, use a different plot color or symbol for each category. Correlation measures the direction and strength of the linear relationship, and written as r.
