Chapter 12 Inference on the Least-squares Regression Line; ANOVA 12.2 Confidence and Prediction Intervals

Confidence intervals are intervals constructed about the predicted value of y, at a given level of x, which are used to measure the accuracy of the mean response of all the individuals in the population. Prediction intervals are intervals constructed about the predicted value of y that are used to measure the accuracy of a single individual’s predicted value.

EXAMPLE. Constructing Confidence Intervals EXAMPLE Constructing Confidence Intervals about the Mean Predicted Value Construct a 95% confidence interval about the predicted mean drill time of all drillings started at a depth of 110 feet. For convenience, the data is given on the following slide.

EXAMPLE Constructing Prediction Intervals about a Predicted Value Construct a 95% prediction interval about the predicted drill time of a single drilling started at a depth of 110 feet.