[R] Normality tests

[Jerome Asselin]

On Tue, 2011-04-26 at 16:15 -0400, Bruce Kindseth wrote:
> I have a large amount of data which I break down into a collection of
> vectors of 100-125 values each.  I would like to test the normality of the
> vectors and compare them.  In the interactive mode I can test any one vector
> using the Shapiro-Wilk test or the Kolmogorov-Smirnov test.  My problem is
> that when I try to write out the results to a file, the term output is a
> mixture of alpha characters along with the number value that I really want.
> How can I get it to write out just the p-values by themselves?

As seen below, the shapiro.test() output is a list of four components.

> names(shapiro.test(rnorm(100, mean = 5, sd = 3)))
[1] "statistic" "p.value"   "method"    "data.name"

You can extract just the p-value with:

> shapiro.test(rnorm(100, mean = 5, sd = 3))$p.value
[1] 0.244

HTH,
Jerome