Interview Q&A / Data Science
Data Science interview questions
Statistics, pandas, cleaning data and exploratory analysis for analyst and data science roles.
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- What is skewness, and what does it tell you about the mean and median?
Skewness measures how lopsided a distribution is. In a right-skewed distribution a long tail of large values pulls the mean above the median; in a left-skewed one the mean falls below the median.
BeginnerQuick answer1 min read - Why are incomes and prices right-skewed, and why does a log transform help?
Such values grow by percentages rather than fixed amounts, so many small effects multiply and produce a long right tail (log-normal shape). Taking the log turns multiplication into addition and usually makes the data close to symmetric.
IntermediateQuick answer1 min read