Type of Tool  RFunction 
Title  ScatterW Interaction 
Programmer/Email  SallyThurston thurston@bst.rochester.edu 
Contributing Site  Rochester 
Description  This function makes a scatterplot of y versus x, with different symbols for the two levels of a dummy variable, where the dummy variable is coded as 0 or 1. From the regression of y on x, dummy variable, interaction (x * dummy variable) and optionally other covariates, the function superimposes on the plot the separate slope of y on x for dummy variable = 0 or 1. These slopes are the predicted lines at mean values of the other covariates (in "covnames" arguments). Options include adding a legend, printing out the regression results to screen, and varying color, size, line type, etc of the lines, as well as plotting symbol and size of the points in the plot. 
Classification Graph Type  Other, Scatterplot 
Graph_Type  Scatterplot, Other 
References 

Datasets  Other 
Data  Any dataset suitable for linear regression with an interaction of a dummy variable with another variable. The function is illustrated with airquality (a default dataset in R) 
Software Program  R 
Software  R version 2.9.0 (20090417) 
Macro Parameters 
### ARGUMENTS: ### tdat is database ### yname is name of y variable in tdat ### xname is name of x variable in tdat, for which we want partial plot ### dummyvar is name of dummy variable for which we want interaction ### x0name is name of x*I(dummy variable==0) (THIS MUST BE PART OF THE DATASET) ### x1name is name of x*I(dummy variable==1) (THIS MUST BE PART OF THE DATASET) ### covnames is vector of names of remaining variables ### txlab is name to go on xaxis of plot (default is xname) ### tylab is name to go on yaxis of plot (default is yname) ### cex.xylab is size of x and y axes ### ttitle is title of plot (default is none) ### cex.title is size of title ### print.results=TRUE if want to print regression results on screen ### ### show.legend=TRUE means include legend ### legend.x0name is what to go in the legend to indicate slope for x0 ### legend.x1name is what to go in the legend to indicate slope for x1 ### legend.loc is location of legend. Possible values are: ### "topleft","topright","bottomleft","bottomright","top","bottom","left","right","center" ### cex.legend is size of legend ### ### confidence.bands=TRUE if want confidence bands on the plot ### lty.lev0 is line type for plotting the line for dummy=0 ### lty.lev1 is line type for plotting the line for dummy=1 ### lty.confidence is line type for the confidence interval ### col.lev0 is color for points and line for dummy=0 ### col.lev1 is color for points and line for dummy=1 ### pch.lev0 is plotting character for dummy=0 ### pch.lev1 is plotting character for dummy=1 ### cex.points is size of points ### ### lwd.slope is lwd for slopes ### lwd.confidence is lwd for confidence bands ### ### The user has the option to either view the plots on the screen ### (save.plots=FALSE, which is the default), or to save the plots ### (save.plots=TRUE) ### If save.plots=TRUE, save either to pdf files (type.plots="pdf", the default) ### or as eps files (type.plots="eps"). The user controls the base name ### of the plots with the basename= argument, so if basename=silly and ### type.plots="pdf" then the plots will be silly1.pdf, silly2.pdf, etc. ### ### ndigits is number of digits to show when printing regression model 
RCode  Attachment 

RCode  scatterWinteraction.R: This is the R function file 
SASCode  Attachment 

SASCode 

StataCode  Attachment 

StataCode 

Other Code  Attachment 

Other Code 

Called Data Manipulation 

Called Tool/Utility 

Called Checking Macro 

Called Other 

CreationDate  September 17, 2012 
RevisionDate 

Example Code  R Example Code 
Example Output  R Example Output 
SAS Examples 

SAS_Example_Code 

SAS_Example_Output 

R Examples 

R_Example_Code 
scatterWinteractionExample.R: scatterWinteraction example file (in R) scatterWinteractionExample.Rnw: scatterWinteraction example file (in Sweave) 
R_Example_Output  scatterWinteractionExample.pdf: scatterWinteraction example output (from running the example Sweave program) 
Stats Examples 

Special Features 

Special Features Attached 

Special Features Text 

Notes1Legend  Section with calls to needed macros 
Notes1 

Notes2Legend  Macro call with fully specified parameters 
Notes2 

Notes3Legend  Section with definitions of global macro parameters 
Notes3 

Notes4Legend  Section with definitions of local macro variables 
Notes4 

See Also 

Checklists 

Stat Tools Disclaimer 

Discliamer 
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Permission 
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF ERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT OLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 
Reference Image 
