Shapiro-Wilk Test for Normality in R
[This article was first published on R – data technik, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.
I think the Shapiro-Wilk test is a great way to see if a variable is normally distributed. This is an important assumption in creating any sort of model and also evaluating models.
Let’s look at how to do this in R!
shapiro.test(data$CreditScore)
And here is the output:
Shapiro-Wilk normality test data: data$CreditScore W = 0.96945, p-value = 0.2198
So how do we read this? It looks like the p-value is too high. But it is not. The data is normal if the p-value is above 0.05. So we now know our variable is normally distributed.
Let’s make a histogram to take a look using base R graphics:
hist(data$CreditScore, main="Credit Score", xlab="Credit Score", border="light blue", col="blue", las=1, breaks=5)
It does look normal from our distribution here:
Great! Now we can make assumptions and perform more tests on our credit scores.
To leave a comment for the author, please follow the link and comment on their blog: R – data technik.
R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job.
Want to share your content on R-bloggers? click here if you have a blog, or here if you don't.