Statistical Sciences 2244A/B Chapter Notes - Chapter 3&4: Confounding, Standard Deviation, Total Variation
25 Dec 2016
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Document Summary
Response variable (dependent): measures an outcome of study. Explanatory variable (independent): may explain or influence changes in a response variable. Response variable depends on the explanatory variable. Scatterplot is best used to show the relationship between quantitative variables. Look at the overall pattern and any deviation when reading scatterplots. Overall pattern can be described by the direction (up/down, left/right), form (ex. linear), and strength of the relationship (how close the points are to each other). Deviation can be described by any outliers. Positive association: two variables are positively associated when above- average values of one tend to accompany above-average values of the other, and below-average values also tend to occur together. Negative association: two variables are negatively associated when above- average values of one tend to accompany below-average values of the other, and vice versa. Categorical variables can be added to scatterplots by using a different plot color or symbol for each category.
