Multiple choice

The frequency table below shows the ages of the students of a class. Their mean age is (approximately) Age (in years) 9 11 13 15 17 Frequency 4 6 10 12 8

  1. 11

  2. 13

  3. 14

  4. 15
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mean = sum(f*x) / sum(f). Sum(f*x) = 9*4 + 11*6 + 13*10 + 15*12 + 17*8 = 36 + 66 + 130 + 180 + 136 = 548. Sum(f) = 4+6+10+12+8 = 40. Mean = 548 / 40 = 13.7, which is approximately 14.

AI explanation

The sum of the products of age and frequency is (9 times 4) + (11 times 6) + (13 times 10) + (15 times 12) + (17 times 8), resulting in 588. The total frequency is 4 + 6 + 10 + 12 + 8, which equals 40. Dividing 588 by 40 gives a mean age of 14.7, which is approximately 14.

Keep practicing — related questions