guide to using minitab 14 for basic statistical applications to accompany business statistics: a...
TRANSCRIPT
Guide to Using Minitab 14 For Basic Statistical Applications
Guide to Using Minitab 14 For Basic Statistical Applications
To Accompany
Business Statistics: A Decision Making Approach, 8th Ed.
Chapter 15:
Multiple Regression and Model Building
By
Groebner, Shannon, Fry, & SmithPrentice-Hall Publishing Company
Copyright, 2011
Chapter 15 Minitab Examples
Multiple Regression First City Real Estate
Multiple Regression – Variance Inflation Factor
First City Real Estate Multiple Regression – Dummy Variable
First City Real Estate Curvilinear Regression Prediction
Ashley Investment Services
More Examples
Chapter 15 Minitab Examples (cont’d)
Second Order Model Ashley Investment Services
Standard Stepwise Regression Lomgmont Corporation
Residual Analysis First City Real Estate
Multiple RegressionFirst City Real Estate
Issue: First City management wishes to build a model that can be used to predict sales prices for residential property.
Objective: Use Minitab to build a multiple regression model relating sales price to a set of measurable variables.
Data file is First City.MTW
Open File First City.MTW
Multiple Regression – First City Real Estate
First click on Stat, then Basic Statistics and finally on Correlation.
Multiple Regression – First City Real Estate
Identify columns for Variables. Click on OK
Multiple Regression – First City Real Estate
The Minitab output shows the correlation (r = -0.073) between Age and Square Feet.
Multiple Regression – First City Real Estate
The correlation between each predictor and Price is highly significant. Thus, each predictor will be inserted into the regression model.
Multiple Regression – First City Real Estate
Click on Stat, then Regression and then Regression again.
Multiple Regression – First City Real Estate
Define the columns containing the Response (Price) and Predictor Variables
Multiple Regression – First City Real Estate
The regression coefficients, R2, S, and sum of squares are all generated by the regression command.
Multiple Regression – First City Real Estate
Issue: First City managers wish to improve the model by adding a location variable.
Objective: Use Minitab to improve a regression model by adding a dummy variable.
Data file is First City.MTW
Multiple Regression – Dummy Variable
First City Real Estate
Multiple Regression – Dummy Variable
First City Real Estate
Open file First City.MTW.
Multiple Regression – Dummy Variable - First City
Click on Stat then Regression and then Regression again.
Multiple Regression – Dummy Variable - First City
Select the columns containing the Response and Predictor Variables.
Multiple Regression – Dummy Variable - First City
The output shows an improved regression model with the variable, Area, included.
Multiple Regression – Dummy Variable - First City
Curvilinear Relationships - Ashley Investment ServicesCurvilinear Relationships - Ashley Investment Services
Issue: The director of personnel is trying to determine whether there is a relationship between employee burnout and time spent socializing with co-workers.
Objective: Use Minitab to determine whether the relationship between the two measures is statistically significant.
Data file is Ashley.MTW
Open File Ashley.MTW
File contains values for 20 Investment Advisors.
Curvilinear Relationships – Ashley Investment Services
To develop the scatter plot first click on Graph button then select Scatterplot
Curvilinear Relationships – Ashley Investment Services
Select Simple
Curvilinear Relationships – Ashley Investment Services
Identify the columns containing the variables to be graphed.
Curvilinear Relationships – Ashley Investment Services
Relationship may be curvilinear – next, fit linear to see model results
Curvilinear Relationships – Ashley Investment Services
Click on Stat then Regression and then Regression.
Curvilinear Relationships – Ashley Investment Services
Identify the columns containing the X and Y variables. Then click OK.
Curvilinear Relationships – Ashley Investment Services
To find a nonlinear model, click on Stat then Regression and select Fitted Line Plot.
Curvilinear Relationships – Ashley Investment Services
Minitab gives the choice of three models, select Quadratic.
Curvilinear Relationships – Ashley Investment Services
This gives the Quadratic Regression Line. The Regression Equation and R-Square value are given.
Curvilinear Relationships – Ashley Investment Services
This gives Regression Equation and R-square value. The R-Square value is larger than that for the linear model.
Curvilinear Relationships – Ashley Investment Services
Interactive Effects - Ashley Investment ServicesInteractive Effects - Ashley Investment Services
Issue: The director of personnel is trying to determine whether there are interactive effects in the relationship between employee burnout and time spent socializing with co-workers.
Objective: Use Minitab to determine whether interactive effects between the two measures are statistically significant.
Data file is Ashley-2.MTW
Interactive Effects – Ashley Investment Services
Open File Ashley-2.MTW
Interactive Effects – Ashley Investment Services
To simplify the next few steps, modify the names of Columns C2 and C3, adding X1 and X2
Interactive Effects – Ashley Investment Services
Using the Calculator tab, set up columns C4, C5 and C6 as:
Column C4 – Expression C2 * C2
Column C5 – Expression C2 * C1
Column C6 – Expression C4 * C3
Identify the column headings
Interactive Effects – Ashley Investment Services
Click on Stat then Regression and then Regression.
Identify the columns containing the X and Y variables. Then click OK.
Interactive Effects – Ashley Investment Services
Interactive Effects – Ashley Investment Services
Regression Coefficients
Issue: The company is interested in analyzing the residuals of the regression model to determine whether the assumptions are satisfied.
Objective: Use Minitab to analyze residuals from a regression model.
Data file is First City-3.MTW
Residual Analysis - First City Real Estate
Residual Analysis - First City Real Estate
Open file First City-3.MTW
Residual Analysis – First City Real Estate
Click on Stat, then Regression and then Regression again.
Residual Analysis – First City Real Estate
Identify the x and y variables.
Residual Analysis – First City Real Estate
R-square = 96.9%
Residual Analysis – First City Real Estate
These are the options using the Graphs button – Select Residuals versus fits.
Residual Analysis – First City Real Estate
Residual Plot versus fitted y values.
Residual Analysis – First City Real Estate
Select Histogram of residuals
Residual Analysis – First City Real Estate
Residual Analysis – First City Real Estate