Question

The data for a sample of 100 gave the regression line equation for age and blood pressure is Ÿ = 100 + 0.96X, and the standard error is 5. The 95% confidence interval of the prediction of the blood pressure of a person who is 43 years old showed that the upper confidence limit is :

Select one:

A. 155.08

B. 159.08

C. 149.09

D. 151.08

Answer 1

Solution :

The 95% confidence interval for a predicted value is given as follows :

Where, is predicted value of y, SE is standard error and t_{(0.05/2, n - 2)} is critical t value.

The regression equation is,

The predicted value of y at x = 43 is given by,

Predicted value of the blood pressure of a 43 years old person is 141.28.

We have, SE = 5 and n = 100

Using t-table we get, t_{(0.05/2, 100 - 2)} = 1.9845

Hence, 95% confidence interval for the predicted value of the blood pressure of a person who is 43 years old is,

The upper confidence limit is 151.08.

Option (D) is correct.