Statistics is one of 10 topics in the Grade 11 Mathematics CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. For the data set 4, 7, 9, 10, 15 (mean = 9), calculate the deviation of the value 15 from the mean.
Answer: 6 — Deviation = value - mean = 15 - 9 = 6.
Easy
2. Why are deviations from the mean squared before being averaged, when calculating variance?
So that negative and positive deviations do not cancel each other out
To make the calculation simpler
Because squaring always gives a smaller number
Squaring is not actually necessary
Answer: So that negative and positive deviations do not cancel each other out — Since deviations above and below the mean would otherwise sum to zero, squaring them (making all values positive) ensures a meaningful measure of spread.
Medium
3. For the data set 4, 7, 9, 10, 15 (mean = 9), the deviations are -5, -2, 0, 1, 6. Calculate the sum of the squared deviations.
