示例:求当mpg为22,weight为2930时,price预测值的置信区间。
-help adjust- 的说明:
ci specifies that a confidence interval be displayed. The confidence
interval is for the displayed estimate as determined by the xb, pr,
or exp option -- producing an interval for the adjusted linear
prediction, probability, or exponentiated linear prediction. When
stdf is specified, a prediction interval is produced, which is, by
definition, wider than the corresponding confidence intervals.