tigerstats (version 0.3.2)

ShallowReg: Regression Line Too Shallow?

Description

The regression line is not as steep as the SD Line (line through point of averages, with slope = sd(y)/sd(x)). The difference is especially noticeable when the scatter plot is the result of a sample from a bivariate normal distribution. This app explains why we use the regression line to predict y from x, even though the SD line appears to be a better linear summary of the scatter plot. Can be used as a starting-point for a discussion of "regression to the mean."

Usage

ShallowReg(n=900,rho=0.5)

Arguments

n

Number of points in the scatter plot.

rho

Target correlation for the scatter plot. Points are selected from a standardized bivariate normal distribution, with correlation rho.

Value

Graphical output.

Examples

# NOT RUN {
if (require(manipulate)) ShallowReg()
# }