Find a 95%prediction interval for the value of the response variable corresponding to the specified value of the predictor variable.

Short Answer

Expert verified

a). From the MINITAB output, the point estimate for the conditional mean of the response variablex=2 is 8.

b). 95% confidence interval for the conditional mean of the response variable is(-5.8858,21.8868).

c). From the MINITAB output, the predictor value of the response variable x=2 is 8.

d). 95% predictor interval for the conditional mean of the response variable is (-17.6059,33.6059).

Step by step solution

01

Finding the point estimate for the conditional mean of the response variable (Part a)

Using MINITAB, calculate the point estimate for the conditional mean of the response variable that corresponds to the predictor variable, x=2.

Procedure for MINITAB:

Step 1: Select Regression > Regression from the Stat menu.

Step 2: In the Response box, type y.

Step 3: In Predictors, fill in the x columns.

Step 4: Under Prediction interval for fresh observations, put 2 in Options.

Step 5: Type 95 in the Confidence Level box.

Step 6: Select Fits, Confidence Limits, SEs of Fits, and Prediction Limits in Storage.

Step 7: Click the OK button.

MINITAB Output:

02

Compute 95% confidence interval for the conditional mean (Part b)

  • MINITAB is used to calculate the 95%confidence interval for the conditional mean of the response variable corresponding to the predictor variable x=2.
  • The 95%confidence interval for the conditional mean of the response variable corresponding to the predictor variable x=2is (-5.8868,21.8868), according to the MINITAB output in part (a).
03

Computation of the response value prediction (Part c)

  • MINITAB is used to calculate the predicted value of the response variable corresponding to the predictor variablex=2.
  • The anticipated value of the response variable corresponding to the predictor value x=2 is 8 according to the MINITAB output in part (a).
04

Compute 95% Prediction interval for the conditional mean (Part d)

  • MINITAB is used to calculate the 95%prediction interval for the conditional mean of the response variable corresponding to the predictor variable x=2.
  • The 95%predictioninterval for the conditional mean of the response variable corresponding to the predictor variable x=2is (-17.6059,33.6059), according to the MINITAB output in part (a).

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Suppose that xand yare two variables of a population with xa predictor variable and ya response variable.

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a. Decide whether you can reasonably apply the conditional mean and predicted value t-interval procedures to the data. If so, then also do parts (b)-(f).

b. Determine and interpret a point estimate for the conditional mean of the response variable corresponding to the specified value of the predictor variable.

c. Find and interpret a 95%confidence interval for the conditional mean of the response variable corresponding to the specified value of the predictor variable.

d. Determine and interpret the predicted value of the response variable corresponding to the specified value of the predictor variable.

e. Find and interpret a 95%prediction interval for the value of the response variable corresponding to the specified value of the predictor variable.

f. Compare and discuss the differences between the confidence interval that you obtained in part (c) and the prediction interval that you obtained in part (e).

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