The ages (in years) of five participants are 22, 24, 26, 28, and 30. What is the variance of these ages?
Show the answer and explanation
Correct answer
A. 8
Principle or equation
Variance is the average of the squared deviations from the mean: σ^2 = (1/n) Σ (x_i - μ)^2.
Why this answer is correct
Mean μ = (22+24+26+28+30)/5 = 130/5 = 26. Deviations: -4, -2, 0, 2, 4. Squared: 16, 4, 0, 4, 16. Sum = 40. Variance = 40/5 = 8.
Example
For data 1, 2, 3: mean = 2, squared deviations 1, 0, 1, sum = 2, variance = 2/3.
This published item includes a stored explanation and passed the platform’s publication workflow. It is independent preparation material, not a claim of an official or recalled examination question.