1. f(Y)
sY = 40
Marginal distribution of Y
MY = 142
Weight Y
sY|X = 36 .
Conditional distribution of Y|X = 68 . . . . . . . . . . . . . . . . . . . . . . .
x1= 60 . . . . . . . . . . . . . . . .
x2= 64 . . . . .
x3= 68
Regression line
Under usual assumptions, the conditional distributions of Y at each level of Height, X, all have the same variance.
Weight & Height for Female UL Students
Height X

2. f(Y)
sY = .8
Marginal distribution of Y
MY = 2.6
GPA Y
sY|X = .64 .
Conditional distribution of Y|X = 28 . . . . . . . . . . . . . . . . . . . . . . .
x1= 12 . . . . . . . . . . . . . . . .
x2= 20 . . . . .
x3= 28
Regression line
Under usual assumptions, the conditional distributions of Y at each level of Height, X, all have the same variance.
Predicting GPA from ACT
ACT X

3. The scattered points spread out quite unequally
Heteroscedastic pattern of errors . xt yt
The scattered points spread out quite unequally