First, determine the predicted mean of the response. Then, examine the prediction interval to determine a range of likely values for a single future value.
The fit is the predicted mean of the response at the specified variable settings. If the relationship between the variables in the model is accurate and does not change, then the mean of the future observations is close to the fit.
The prediction interval is a range that is likely to contain a single future response for a specified combination of variable settings. If you collect another data point at the same variable settings, then the new data point is likely to be within the prediction interval.
Heat Flux = 389.17 + 2.125 East + 5.3185 South − 24.132 North
Key Results: Fit, 95% PI
In these results, the fit is 206.783, which is the predicted mean of the heat flux when East is 36, South is 33, and North is 18. At these same settings, the 95% prediction interval, which is a range of likely values for a single future value, is 187.126 to 226.441.