Question 1
The model
E(
y) =
β0 +
β1x1 +
β2x2 +
β3x3 was used to relate
E(
y) to a single qualitative variable. How many levels does the qualitative variable have?
Question 2
An elections officer wants to model voter turnout (
y) in a precinct as a function of the type of precinct.
Consider the model relating mean voter turnout,
E(
y), to precinct type:
E(
y) =
β0 +
β1x1 +
β2x2, where
x1 = 1 if urban, 0 if not
x2 = 1 if suburban, 0 if not
(Base level = rural)
The
p-value for the test
H0:
β1 =
β2 = 0 is .14. Interpret the result.
◦ Reject
H0 at
α = .10; the model is useful for predicting voter turnout.
◦ Reject the model since it only explains 14% of the variation.
◦ Do not reject
H0 at
α = .10; there is no evidence of a difference between the mean voter turnouts for urban, suburban, and rural precincts.
◦ Reject
H0 at
α = .01; there is evidence of a difference between the mean voter turnouts for urban, suburban, and rural precincts.