Using the regression line y = 1 + 2x, what is the predicted value when x = 4?

Using the regression line y = 1 + 2x, what is the predicted value when x = 4?

• A. 10
• B. 7
• C. 8
• D. 9

Answer: (D)

In a regression line, the predicted value of y for a given x comes from y = intercept + (slope × x). Here the intercept is 1 and the slope is 2. Plugging in x = 4 gives y = 1 + (2 × 4) = 1 + 8 = 9. So the predicted value is 9, which matches the correct choice.

In a regression line, the predicted value of y for a given x comes from y = intercept + (slope × x). Here the intercept is 1 and the slope is 2. Plugging in x = 4 gives y = 1 + (2 × 4) = 1 + 8 = 9. So the predicted value is 9, which matches the correct choice.