Describing Data skill check
Frequency tables, measures of centre and spread, quartiles, outliers, z-scores, shape, robust summaries and grouped data — calculated on fresh numbers and interpreted. 12 questions, 30 minutes, 70% to pass.
- Questions
- 12
- Time
- 30 min
- Pass mark
- 70%
- Retake after
- 6 h
Skills covered
Build a frequency table · Calculate relative frequencies · Read a two-way table · Find a median · Choose a measure of centre · Calculate a weighted mean · Average growth rates with the geometric mean · Choose the right kind of mean · Calculate a variance · Calculate a standard deviation · Choose between n and n − 1 · Calculate quartiles and percentiles · Calculate the interquartile range · Find a percentile rank · Explain why software quantiles differ · Give a five-number summary · Read and build a box plot · Flag outliers with the 1.5 × IQR rule · Decide what to do with outliers · Calculate and use z-scores · Compare values on different scales · Apply the empirical rule with care · Measure and describe skewness · Interpret excess kurtosis · Describe the shape of a distribution · Calculate the median absolute deviation · Calculate trimmed and winsorized means · Calculate and interpret the coefficient of variation · Choose robust summaries · Estimate a mean from grouped data · Estimate a median from grouped data · Explain the limits of grouped data · Match summaries to the data · Write a summary for a report · Round and present summaries sensibly
Covers Track 2: Describing Data. Passing it, together with completing every lesson, earns the track certificate.
How it works
- Questions are drawn from this assessment's own bank, with numbers generated for your attempt.
- Your answers save automatically. Nothing is graded until you submit or the time runs out (the server keeps the time).
- No hints or feedback during the attempt; full worked solutions afterwards.
- You may use a calculator, the lab and your notes. The assessment is not proctored.