Question

7. If Mean 45, Ef; = 20 then find Efixi .​

Answer 1

Step-by-step explanation:

Given:-

$\sf Mean=45$

$\sf \Sigma f =20$

To find:-

$\sf \Sigma fixi$

Solution :-

We know that

$\boxed{\sf Mean=\dfrac {\Sigma fixi}{\Sigma fi}}$

• Substitute the values

$\\\qquad\quad\sf{:}\leadsto 45=\dfrac {\Sigma fixi}{20}$

$\\\qquad\quad\sf{:}\leadsto \Sigma fixi=45×20$

$\\\qquad\quad\sf{:}\leadsto \Sigma fixi=900$

More to know:-

Formula of statistics:-

$\boxed {\begin{minipage}{9.2 cm}\\ \dag \: \underline{\Large\bf Formulas\:of\:Statistics} \\ \\ \bigstar \: \underline{\rm Mean:} \\ \\ \bullet\sf M=\dfrac {\Sigma x}{n} \\ \bullet\sf M=a+\dfrac {\Sigma fy}{\Sigma f} \\ \\ \bullet\sf M=A +\dfrac {\Sigma fy^i}{\Sigma f}\times c \\ \\ \bigstar \: \underline{\rm Median :} \\ \\ \bullet\sf M_d=\dfrac {n+1}{2} \:\left[\because n\:is\:odd\:number\right] \\ \bullet\sf M_d=\dfrac {1}{2}\left (\dfrac {n}{2}+\dfrac {n}{2}+1\right)\:\left[\because n\:is\:even\:number\right] \\ \\ \bullet\sf M_d=l+\dfrac {m-c}{f}\times i \\ \\ \bigstar \: {\boxed{\sf M_0=3M_d-2M}}\end {minipage}}$