Z-scores and standard deviations: calculation and interpretation
I explain distance from the mean, show how to check the calculation and identify what a z-score cannot establish about rarity.
Knowledge base / Statistics
Statistics for data analysis
Articles on statistics in data analysis: standard deviation, z-scores, analysis methods and common mistakes in conclusions.
4 articles
In data analysis I use statistics mainly for three things: describing a distribution, comparing groups and judging whether an observed difference could be due to chance. An average without information about spread can mislead, and a chart without group sizes often promises more than the data shows.
Short entries for this section are still in preparation. In the meantime, below you will find articles on standard deviation and z-scores, on analysis methods and on the statistical mistakes I see most often in conclusions.
Articles on this topic
Short entries for this section are still in preparation. In the meantime, these articles cover the most important parts of the work.
5 statistical mistakes analysts make: check the conclusion
I show how correct figures can support an incorrect story, and how to check denominators, samples, distributions and the scope of a recommendation.
Data analysis methods: from business question to decision
Conversion falls while group rates stay unchanged. A shop example shows how to choose an analytical method and establish what remains unknown.
How to Analyze Election Polls – Understanding Statistical Error and Why Polls Can Be Wrong
