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7.4.4 Statistics, SPM Paper 1 (Short Questions)

September 18, 2019October 22, 2013 by

Question 7:
A set of data consists of twelve positive numbers.

$It is given that Σ {(x - \bar{x})}^{2} = 600 and Σ x^{2} = 1032.$
Find
(a) the variance
(b) the mean

Solution:
(a)

$\begin{array}{l} Variance = \frac{Σ {(x - \bar{x})}^{2}}{N} \\ = \frac{600}{12} \\ = 50 \end{array}$

(b)

$\begin{array}{l} Variance = \frac{Σ x^{2}}{N} - {(\bar{x})}^{2} \\ 50 = \frac{1032}{12} - {(\bar{x})}^{2} \\ {(\bar{x})}^{2} = 86 - 50 \\ = 36 \\ \bar{x} = 36 \end{array}$

1 thought on “7.4.4 Statistics, SPM Paper 1 (Short Questions)”

james

August 17, 2019 at 3:50 pm | Reply

WHAT YEAR IS THIS ???

1 thought on “7.4.4 Statistics, SPM Paper 1 (Short Questions)”

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