A sociologist examines the relationship between the poverty rate and several socioeconomic factors. For the 50 states and the District of Columbia (n = 51), he collects data on the poverty rate (y, in %), the percent of the population with at least a high school education (x1), median income (x2, in $1000s), and the mortality rate per 1,000 residents (x3). He estimates the following model as y = b0 + b1Education + b2Income + b3Mortality + e. The following ANOVA table shows a portion of the regression results.

df

SS

MS

F

Regression

3

417.3

139.1

94.6

Residual

47

69.1

1.47

Total

50

486.4

Coefficients

StandardError

t-stat

p-value

Intercept

60.3

4.8

12.47

1.65E-16

Education

0.43

0.05

7.78

5.45E-10

Income

0.20

0.03

7.75

6.02E-10

Morality

0.08

0.17

0.47

0.6438

The coefficient of determination indicates that ___.

Group of answer choices

a. 14% of the variation in the poverty rate is explained by the regression model.

b. 14% of the variation in median incomes is explained by the sample regression equation.

c. 86% of the variation in the poverty rate is explained by the sample regression equation.

d. 86% of the variation in median incomes is explained by the sample regression equation.