13 2 Probability – Class 9TH Math | Theory of Intelligence

13.4 Relative Frequency as an Estimate of Probability

Relative frequency tells us how often a specific event occurs relative to the total number of frequency event or trials. It is calculated by using the following method:

\text{Relative frequency} = \dfrac{\text{Frequency of specific event}}{\text{Total frequency}} = \dfrac{x}{N}, \quad \text{where } N = \Sigma f

Example 8

Find the relative frequency of the given date.

$X$	$2$	$3$	$4$	$5$	$6$	$7$	$8$
$f$	$3$	$5$	$6$	$9$	$10$	$8$	$2$

Solution:

$X$	$f$	Relative frequency
$2$	$3$	$\dfrac{3}{43} = 0.07$
$3$	$5$	$\dfrac{5}{43} = 0.12$
$4$	$6$	$\dfrac{6}{43} = 0.14$
$5$	$9$	$\dfrac{9}{43} = 0.21$
$6$	$10$	$\dfrac{10}{43} = 0.23$
$7$	$8$	$\dfrac{8}{43} = 0.19$
$8$	$2$	$\dfrac{2}{43} = 0.04$
Total	$\Sigma f = 43$

13.4 Relative Frequency as an Estimate of Probability

Example 8

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