(pg. 150-151) Measuring Linear Association: Correlation Linear relationships are important because a straight line is a simple pattern that is quite common. Unfortunately, our eyes are not good judges of how strong a linear relationship is. Definition Correlation: – The measures the strength of the linear relationship between two quantitative variables. correlation r is always between ___ and ___. r > 0 indicates a ___________ association. r < 0 indicates a negative association. r Values of near 0 indicate a very _________ linear relationship. r The strength of the linear relationship _____________ as moves away from 0 towards -1 or 1. r The extreme values = -1 and = 1 occur only in the case of a _____________ linear relationship. r r Estimate the correlation and interpret in context. r Formula Correlation: (pg. 152) – The correlation between and is: r x y It is on your formula sheet!
Measuring Linear Association: Correlation (pg. 150-151) Linear relationships are important because a straight line is a simple pattern that is quite common. Unfortunately, our eyes are not good judges of how strong a linear relationship is. Definition – Correlation: The correlation r measures the strength of the linear relationship between two quantitative variables. r is always between ___ and ___. r > 0 indicates a ___________ association. r < 0 indicates a negative association. Values of r near 0 indicate a very _________ linear relationship. The strength of the linear relationship _____________ as r moves away from 0 towards -1 or 1. The extreme values r = -1 and r = 1 occur only in the case of a _____________ linear relationship. Estimate the correlation r and interpret in context. Formula – Correlation: (pg. 152) The correlation r between x and y is: It is on your formula sheet!
3.1a_-_scatterplots_and_correlation.docx