$x_{mean}=\dfrac{x_1+x_2+x_3+…..+x_n}{n}$
Using Empirical formula,
Mode = 3Median – 2 Mean
3Median = Mode + 2Mean
Median = $\dfrac{(Mode + 2Mean)}{3}$
Median = $\dfrac{[7 + 2(8)]}{3} = \dfrac{(7 + 16)}{3} = \dfrac{23}{3}$
For the given data, there are two middle terms, 16 and 17.
Hence, median = $\dfrac{(16 + 17)}{2} = \dfrac{33}{2}$
Mean of AM = 10
$\dfrac{(a + a + 3 + a + 6 + a + 9 + a + 12)}{5}$ = 10
5a + 30 = 50
5a = 20
a = 4
Class mark = $\dfrac{(Upper \: limit + Lower \: limit)}{2}$
= $\dfrac{(15 + 10)}{2}$
= $\dfrac{25}{2}$
= 12.5
The abscissa of the point of intersection of the less than type and of the more than type cumulative frequency curves of a grouped data gives its median.
The abscissa of the point of intersection of the less than type and of the more than
type cumulative frequency curves of a grouped data gives its median.
The mean for a given data can be calculated using either of the following methods.
(i) Direct method
(ii) Assumed mean method
(iii) Step deviation method