Question

When using a regression equation, the difference between the formulas used to calculate the confidence interval estimate and prediction interval estimate is ______.

Answer 1

the addition of "1" to the quantity under the radical sign.

Explanation:

Using a regression equation :

The confidence interval is obtained using the relation :

yhat ± t(α/2) * s√(1/n + (Xp - xbar)²/SSx)

yhat = Predicted value

s = estimated standard deviation of yhat

x = Xp

The prediction interval is obtained using the relation :

yhat ± t(α/2) * s√(1 + 1/n + (Xp - xbar)²/SSx)

Hence, from the formula stated abibeb, we can see that, the only difference is the 1 added to the prediction interval formula.