4.3

what does R squared measure

percent or proportion of total variation in the response variable is explained by the least squared regression line

Rsquared interpretation is always given in what format

percentage

how to interpret R squared each time

% of the change in "y" can be explained by the least squared regression line - fill in percent and fill in y variable

unexplained percentage in R squared

100%- R squared= the unexplained percentage

total deviation

= unexplained vairation + explained variation or y-ybar=(y-ybar)+ (yhat-ybar)

residual plot is

a scatterplot of the residuals (y axis) against the explanatory variable (x axis)

the coefficient of determination will always be

between 0 and 1

R squared

coefficient of determination

purpose of residual analysis

d/t if linear model appropriate d/t if variance of the residuals is constant check for outliers

interpret residual plot

if shows a discernible pattern then may not be linearly related

If R Squared = 1

line explains 100% of the variation in the response variable

if R squared = 0 this means

line has no explanatory value

how to determine if linear model is appropriate

residual plot

how to draw residual plot in calculator

variables in list format do a scatter plot first stat, calc, #4, l1 and l2, line reg- little r must run lin reg every time prior to residual plot x list- L1, Ylist, 2nd STAT, #7 for RESID zoom, #9