Biology 2244A/B Lecture 16: Regression – hypothesis test for linearity
1 Jan 2017
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Lecture 16 regression hypothesis test for linearity. Difference in slope does no impact correlation. Correlation tells you of direction and magnitude tells you how strong the relationship is: how close points lie to imaginary lie. If have a tight fit = large value, close to 1 or -1. If they don"t lie close, end up with a value close to 0. Doesn"t tell you how much y increases/decrease with x. Does not tell you about the nature of relationship. Tells you about strength and direction but not the nature of the relationship: does not tell you about slope regression does. Clicker q: a plant population is known to have a weak positive relationship between age (years) and height (inches). Just because a population has a positive relationship does not mean that every sample we take will show the same relationship. Have our sample and our population: r estimates a population parameter.
