lecture7_6slides

lecture7_6slides - Statistics 528 - Lecture 7 Section 2.2 -...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Statistics 528 - Lecture 7 1 Statistics 528 - Lecture 7 Prof. Kate Calder 1 Section 2.2 - Correlation Statistics 528 - Lecture 7 Prof. Kate Calder 2 Sometimes it is difficult to judge the strength of a relationship by eye => need a numerical measure of strength to supplement a scatterplot CORRELATION (r) - measures the strength and direction of the linear relationship between two quantitative variables. where and are the means of the x -values and y -values, respectively, and s x and s y are the corresponding standard deviations. = ± ± ± ² ³ ´ ´ ´ µ - ± ± ² ³ ´ ´ µ - ± ² ³ ´ µ - = n i y s y i y x s x i x n r 1 1 1 x y Statistics 528 - Lecture 7 Prof. Kate Calder 3 Correlation is an “average” of the product of the standardized values of the two variables. The sign of r gives the direction of the relationship. r > 0 => positive association r < 0 => negative association Strength is on a scale 0 to 1. So
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

lecture7_6slides - Statistics 528 - Lecture 7 Section 2.2 -...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online