right click on the picture to view it fully Prices of a samp

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Prices of a sample of generic drugs were regressed on the prices of the brand-name equivalents. The regression equation is Generic = -4.4 + 0.689 Brand Predicted Values for New Observations Values of Predictors for New Observations 2. Which of these is true about the confidence interval (C.l.)? a. For large samples and explanatory values not far from their mean. it is approximately y plus minus 2s. b. For large samples. and explanatory values not far from their mean. it is approximately y plus minus 2 s/root n.

Solution

The appropriate choice is (b).

In regression analysis, for the large samples the confidence interval approximately equivalent to y^+/-(2s/sqrt(n))