Question

The IQ scores and science test scores of fourth grade students is given by the regression line ŷ = −20.3 + 0.7489s, where ŷ is the predicted science score and s is the IQ score. An actual science test score for a student is 52.6 with an IQ of 100.

Find and interpret the residual.

−1.99; The regression line under predicts the student's science test score.
1.99; The regression line over predicts the student's science test score.
1.99; The regression line under predicts the student's science test score.
−1.99; The regression line over predicts the student's science test score.

Answer 1

24

Explanation:

24

Explanation:

Given the equation of the regression line :

y = - 20.3 + 0.489s

where ŷ is the predicted science score

s = IQ score

An actual science test score for a student is 52.6 with an IQ of 100.

Find and interpret the residual.

The predicted science test score for a student with an IQ of 100 is :

y = - 20.3 + 0.489(100)

y = - 20.3 + 48.9

y = 28.6

The residual = actual - predicted score

The residual = 52.6 - 28.6 = 24

Hence, the residual is 24 which is the error in prediction made about the actual score.