Descriptive Statistics

What this module covers

By the end of it

• Compute and choose between measures of central tendency — mean, median, mode — and know when each lies
• Quantify spread — range, variance, standard deviation, IQR, MAD, coefficient of variation
• Describe shape — skewness and kurtosis — and connect them to a histogram
• Use percentiles, quantiles, and the five-number summary
• Standardise data with z-scores and explain what a z-score means
• Detect outliers with the IQR rule and the z-score rule
• Produce grouped summaries with groupby().agg() and read DataFrame.describe() critically