ICSEClass XMathematicsMeasures Of Central Tendency03 Mark2025 Moderate

QQuestion

For the following frequency distribution, find:

(a) the mean, to the nearest whole number.

(b) the median.

x 10 11 12 13 14 15 16
f 3 2 2 6 3 5 3

Exam-ready answer 03 Mark

Answer

8(ii)

Prepare the calculation table:

x f fx Cumulative frequency
10 3 30 3
11 2 22 5
12 2 24 7
13 6 78 13
14 3 42 16
15 5 75 21
16 3 48 24

Σf = 24 and Σfx = 319.

(a) Mean = \frac{\Sigma \mathrm{fx}}{\Sigma \mathrm{f}}

⇒ Mean = \frac{319}{24}

⇒ Mean = 13.291…

To the nearest whole number, mean = 13.

(b) N = 24, so the middle observations are the 12th and 13th.

From the cumulative frequencies, both the 12th and 13th observations have x = 13.

Median = \frac{13+13}{2}

⇒ Median = 13

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