STAT 1020 Chapter Notes - Chapter 6, 12: Summary Statistics
31 Dec 2018
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Correlation coefficient (r) measures the strength and direction of the linear relationship between quantitative variables: scale: -1(negative relationship to 1 (positive relationship) 0 = no relationship. The correlation coefficient is a summary statistic (like the mean and sd). It summarizes the strength of a linear relationship. It uses sd as a ruler for both the x"s and y"s". The correlation coefficient (r) is the almost average of the products of standard units r. X yz z n 1 n-1 (number of points minus 1) = almost average. Zx (x in standard units)= (x minus xbar (average) divided by sd of x) same goes for y. Pew research tracks the behavior of online adults . Facebook, 24% used twitter, and 22% used both. For randomly selected online adult, what is the probability that the person: facebook- . 79, twitter- . 29, both - . 22, neither- . 19, twitter not facebook - . 02, facebook not twitter . 57.
