Minitab Help 10: Model Building

Minitab Help 10: Model Building

Minitab®

Martians (underspecified model)

  • Perform a linear regression analysis of weight vs height + water. Click "Storage" and select "Fits" before clicking "OK."
  • Select Calc > Calculator, type "FITS0" in the box labeled "Store results in variable," type "if(water=0,FITS)" in the box labeled "Expression," and click "OK." Repeat to create "FITS10" as "if(water=10,FITS)" and "FITS20" as "if(water=20,FITS)."
  • Perform a linear regression analysis of weight vs height (an underspecified model). Click "Storage" and select "Fits" before clicking "OK." The resulting variable should be called "FITS_1."
  • Create a basic scatterplot but select "With Groups" instead of "Simple." Plot "weight" vs "height" with "water" as the "Categorical variable for grouping."
  • To add parallel regression lines representing the different levels of water to the scatterplot, select the scatterplot, select Editor > Add > Calculated Line, select "FITS0" for the "Y column" and "height" for the "X column." Repeat to add the "FITS10" and "FITS20" lines.
  • To add a regression line representing the underspecified model to the scatterplot, select the scatterplot, select Editor > Add > Calculated Line, select "FITS_1" for the "Y column" and "height" for the "X column."

Cement hardening (variable selection using stepwise regression)

IQ and body size (variable selection using stepwise regression)

Blood pressure (variable selection using stepwise regression)

Cement hardening (variable selection using best subsets regression)

IQ and body size (variable selection using best subsets regression)

Blood pressure (variable selection using best subsets regression)

Peruvian blood pressure (variable selection using best subsets regression)

Measurements of college students (variable selection using stepwise regression)

  • Conduct stepwise regression for Height vs LeftArm + LeftFoot + LeftHand + HeadCirc + nose + Gender.
  • Change the "Method" to "Backward elimination" or "Forward selection."

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