**Instructions:** Use this prediction interval calculator for the mean response of a regression prediction. Please input the data for the independent variable \((X)\) and the dependent variable (\(Y\)), the confidence level and the X-value for the prediction, in the form below:

#### Prediction Interval for the Mean Response

The Prediction Interval for an individual predictione corresponds to the calculated confidence interval for the individual predicted response \(\hat{Y}_0\) for a given value \(X = X_0\). First, we need to know the mean squared error:

\[\hat{\sigma}^2 = \displaystyle \frac{SSE}{n-2}\]Then, the \(1-\alpha)\times 100 \)% confidence interval for the the individual prediction \(\hat{Y}_0\) is

\[CI = \displaystyle \left( \hat{Y}_0 - t_{\alpha/2; n-2} \sqrt{ \hat{\sigma}^2 \left(1 + \frac{1}{n} + \frac{\left(X_0 - \bar X\right)^2}{SS_{XX}}\right) },\hat{Y}_0 + t_{\alpha/2; n-2} \sqrt{ \hat{\sigma}^2 \left(1+ \frac{1}{n} + \frac{\left(X_0 - \bar X\right)^2}{SS_{XX}}\right) } \right)\]If you are interested rather in a confidence interval for the mean response, please use instead this confidence interval calculator for regression predictions.

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