BIOL-337 Chapter Notes - Chapter 15: The Miracles, Frequency Distribution, Multivariate Normal Distribution
18 Apr 2018
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Def: correlated: two numerical variables are associated. Ex: brain and body size are positively correlated across (cid:373)a(cid:373)(cid:373)al"s species: large bodied mammals have large brains small bodied mammals have small brains: correlation coefficient. Describes the strength/direction of association between 2 numerical variables. Can put confidence bounds on the estimate of the correlation coefficient. How deviations in x and y vary together. Deviation= difference between an observation and its mean. If observation (i) is positive for x and. If observation is below the mean for x and y, then numerator is negative. *sum of product adds all the products of deviation. If most of the observations are in the top right corner = positive sum. If most of the observations are in the bottom left corner = negative sum. If the observations are in all 4 corners= sum of products are around 0. If the observations are in the lower left and top right = positive sum.
