Post 1 Introduction to Statistical analysis of data with outliers
Post 2 Correlation when outliers in the data.
Post 3 Trend when outliers in the data.
Post 4 Correlation and trend when an outlier is added. Example
Post 5 Compare Kendall-Theil and OLS trends. Simulations.
Post 6 Detect serial correlation when outliers. Simulations.
The posts are gathered in this pdf document.
Start of post 4:
Correlation and trend when an outlier is added.
This blog post contains an example that demonstrates the shortcomings of the mostly used methods to calculate trends and correlations when an outlier is added to the data. It demonstrates that alternative methods based on medians and ranks are more robust against outliers.