If the variance of the frequency distribution
$x$
$c$
$2 c$
$3 c$
$4 c$
$5 c$
$6 c$
$f$
2
1
1
1
1
1
is 160 , then the value of $c \in N$ is

Question

If the variance of the frequency distribution x c 2c 3c 4c 5c 6c f 2 1 1 1 1 1 is 160 , then the value of c ∈N is

Accepted Answer

Correct answer: A. (a) x C 2 C 3 C 4 C 5 C 6 C f 2 1 1 1 1 1 x= (2+2+3+4+5+6 )C7= 22C7 Var ⁡ (x )= c^2(2+2^2+3^2+4^2+5^2+6^2)7 - ( 22c7 )^2 = 92c^27-c^2 48449 = (644-484 )c^249= 160c^249160= 160 c^249 ⇒c=7

$If the variance of the frequency distribution x c 2 c 3 c 4 c 5 c 6 c f 211111 is 160 , then the value of c \in N is$

Solution

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