Can I predict the height of children from the height of their mother and father?
Can I predict product purity from the reaction temperature and reactor residence time?
Can I predict the hardness of a steel bar from the tempering temperature, bar size and time at temperature?
Can I predict a student's university grade point average on the basis of their high school grade point average and SAT score?
Can I predict my ice cream sales based on the temperature and humidity?
Multiple linear regression is used to answer these types of questions by finding if there is a linear relationship between an effect (ice cream sales) and possible causes (temperature and humidity). The SPC for Excel software contains regression as well as stepwise regression.
Watch a Video Featuring SPC for Excel's Regression Analysis
Multiple Linear Regression/Stepwise Regression and SPC for Excel
Multiple linear regression is a method used to model the linear relationship between a dependent variable and one or more independent variables. It allows you to examine what independent variables (x) impact a response variable (y) and by how much. SPC for Excel contains multiple linear regression that allows you to see if a set of x values impact the response variable. The output from the SPC for Excel software includes an in-depth analysis of residuals with potential outliers in red as well as multiple charts to analyze the results. You can easily remove independent variables as well as observations from the data and rerun the regression. You can also transform the y variables. SPC for Excel also contains stepwise regression. Stepwise regression is process of building a model by successively adding or removing variables based solely on the p values associated with the t statistic of their estimated coefficients. A complete list of regression features is given below.
Multiple Linear Regression Features
ANOVA for Model
Variables Output
Coefficients
Standard error
t statistic, p value
95% confidence limit
VIF
Standardized coefficients
Regression statistics
R2
Adjusted R2
Mean, standard error
Coefficient of variation
Durbin-Watson statistic
PRESS
R2 prediction
Residuals analysis
Residuals
Leverage
Standardized residuals
Internally studentized residuals
Externally studentized residuals
DFFITS
Cook's distance
Standard error of estimated mean
95% confidence limits of estimate means
Potential outliers in red
Residuals charts (raw, standardized, internally or externally studentized residuals)
Normal plot
Versus predicted values
Versus observation number
Versus predictor variables
Other charts
Predicted vs actual
DFFITS, Cook's distance and leverage versus observation number
Remove variables
Remove observations
Transform y variables
p values < 0.05 in red
Stepwise Regression Features
Changed p values to enter and to remove variables
Fit intercept
Output lists each step of the regression where a variable is added or removed
Output includes the coefficient, t statistic and p value for each included variable in each step
Output includes sigma, R2 , and R2 adjusted for each step