A Public Health Researcher Wants to Use Regression to Predict $\quad \mathrm { y } =$

A public health researcher wants to use regression to predict the sun safety knowledge of pre-school children. The researcher randomly sampled 35 preschoolers, assigned them to one of
Two groups, and then measured the following three variables: SUNSCORE: $\quad \mathrm { y } =$ Score on sun-safety comprehension test
READING: $\quad \mathrm { x } _ { 1 } =$ Reading comprehension score
GROUP: $\quad x _ { 2 } = 1$ if child received a Be Sun Safe demonstration, 0 if not
A regression model was fit and the following residual plot was observed.

Which of the following assumptions appears violated based on this plot?

A) The mean of the errors is zero
B) The errors are independent
C) The errors are normally distributed
D) The variance of the errors is constant