Coding Grandmaster · project 25 of 46 · premium, free for now

Averages

Write mean(data), median(data) and mode(data). If several values tie for most common, mode returns the smallest of them. Print all three for the list.

Learn

Three averages, three questions. The mean adds everything and divides by how many. The median is the middle value of the sorted list (or the mean of the two middle ones). The mode is the most common value. The median ignores extreme values, so for incomes or house prices it is often more honest than the mean.

Your task

Write mean(data), median(data) and mode(data). If several values tie for most common, mode returns the smallest of them. Print all three for the list.

Stretch challenge

Add one huge value to the list and see which average moves most.

← How computers fake randomness How spread out? →

Python

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Keep going in Coding Grandmaster

How spread out?

Write data_range(data), variance(data) and std_dev(data) (population versions, dividing by n). Print them for the data, rounding the standard deviation to 4 decimal places.

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Write quartiles(data) returning (q1, q2, q3) by the method above, and outliers(data) returning the sorted list of outliers by the 1.5 × IQR rule.

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A histogram in text

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Do two things move together?

Write correlation(xs, ys) that returns Pearson's r rounded to 4 decimal places. Print it for study hours against marks.

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Scaling and z-scores

Write min_max(values) and z_scores(values) (use the population standard deviation). Both return lists with each number rounded to 2 decimal places.

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Practise the idea

🔢 Play Number Sense Lab

Explore place value, number patterns, rounding, factors and multiples with short adaptive challenges.

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FAQ

Averages: common questions

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