1.3.3.21.4. Normal Probability Plot: Data is Skewed Right

1. Exploratory Data Analysis
1.3. EDA Techniques
1.3.3. Graphical Techniques: Alphabetic
1.3.3.21. Normal Probability Plot

1.3.3.21.4. Normal Probability Plot: Data is Skewed Right

Normal Probability Plot for Data that is Skewed Right

Conclusions

The normal probability plot shows a strongly non-linear pattern. Specifically, it shows a quadratic pattern in which all the points are below a reference line drawn between the first and last points.
The normal distribution is not a good model for this data.

Discussion

This quadratic pattern in the normal probability plot is the signature of a significantly right skewed data set. Likewise, if all the points on the normal probability plot fell above the reference line connecting the first and last points, that would be the signature pattern for a significantly left skewed data set.

In this case, we can quite reasonably conclude that we need to model this data with a right skewed distribution such as the Weibull or lognormal.