Statistics

2 articles

Data Science 02 Sep 2026 5 min read

Robust Outlier Detection with Median Absolute Deviation

Outlier detection often begins with a rule such as “flag values more than three standard deviations from the mean.” That works reasonably well for approximately normal data without severe contamination, but the same extreme observations you want to detect can move both the mean and the standard deviation. Median absolute deviation, usually abbreviated MAD, provides a more robust alternative. Why mean and standard deviation can be fragile Consider response times in milliseconds:

Data Science Statistics

Data Science 02 Sep 2026 5 min read

Bootstrap Confidence Intervals with Resampling

A point estimate hides uncertainty. Reporting that median latency is 180 ms or a conversion-rate difference is 1.4 percentage points does not show how much that estimate might move if another sample were collected. Bootstrap resampling is a practical way to estimate sampling uncertainty when deriving an analytic formula is difficult or when the statistic is not a simple mean. The bootstrap idea Given an observed sample of size n:

Data Science Statistics