Question 48
Measures of Dispersionx: 1, 2, 3, 4, 5
f: 2, 1, 2, 1, 2
Find the variance of the frequency distribution above.
- A.3/2
- B.9/4
- C.5/2
- D.3
Show the answer and explanation
Answer: B (9/4)
Explanation
Σf = 8 and Σfx = 24, so the mean is 3. Σf(x − 3)² = 2(4) + 1(1) + 0 + 1(1) + 2(4) = 18. Variance = 18/8 = 9/4.