MATH 109 Lecture 10: Chapter 8
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According to a recent study by researchers from konkuk university in. Suppose we want to know whether the weights of students are related to their heights. Correlation coefficient: the point of averages of a cloud. Each point in a cloud can be represented by a pair of numbers, say (x,y) We can use the average of the x-values and the average of the y-values to define a point of averages for the cloud. The point that has these averages as coordinates is called the point of averages: the sd of the x-values is called the horizontal sd. Most of the points will be within 2 horizontal sds on either side of the point of averages. o. To measure the association, we need one more statistic known as the correlation coefficient. When r lies on the interval: (-1. 0, -. 8) or (1. 0, . 8) strong, (-. 8, -. 5) or (. 8, -5) moderate, (-. 5,. 5) weak. The correlation coefficient r is computed as follows:
