Introduction to Statistics (MAT/SST 115.03 2008S)
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Preliminary Notes
You create a normal probability plot with qqnorm
.
qqnorm(data
)
There are two strategies for making normal probability plots: You can
put the actual values on the X axis and the expected values on the Y axis,
or vice versa. By default, the expected values are the x values. You
tell R to put the data values along the x axis with datax=T
.
qqnorm(data
, datax=T)
We may also want to add a label, which we do with the ylab
parameter.
qqnorm(data
, datax=T, ylab="LABEL
")
Finally, it is helpful to put a normal line through the data to help see how
much the data deviate. We use qqline
for this
purpose. (If you've specified datax=T
for
qqnorm
, you should also specify it for
qqline
.)
qqnorm(data
, datax=T, ylab="LABEL
") qqline(data
, datax=T)
Primary: [Front Door] [Syllabus] [Current Outline] [R] - [Academic Honesty] [Instructions]
Groupings: [Applets] [Assignments] [Data] [Examples] [Handouts] [Labs] [Outlines] [Projects] [Readings] [Solutions]
External Links: [R Front Door] [SamR's Front Door]
Copyright (c) 2007-8 Samuel A. Rebelsky.
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