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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- How do you detect outliers using the IQR and z-score methods?
With the IQR method, a value is an outlier if it lies below Q1 minus 1.5 times the IQR or above Q3 plus 1.5 times the IQR. With the z-score method, a value is flagged if it is more than about 3 standard deviations from the mean. IQR is more robust for skewed data and small samples, because outliers inflate the mean and standard deviation.
IntermediateIn-depth4 min read - How do you read a box plot?
A box plot shows the median, Q1 and Q3 as a box, whiskers reaching the furthest points within 1.5 x IQR of the box, and dots for points beyond that. It summarises centre, spread, skew and outliers in one compact picture.
BeginnerQuick answer1 min read