A random variable X has the following probability distribution: X = x i - 2 - 1 0 1 2 P X = x i 1 6 k 1 4 k…

A random variable X has the following probability distribution:

X=xi -2 -1 0 1 2
PX=xi 16 k 14 k 16

The variance of this random variable is

  1. 0
  2. 524
  3. 324
  4. 74

Solution

A random variable X has the following probability distribution:

X=xi -2 -1 0 1 2
PX=xi 16 k 14 k 16

The given distribution is the probability distribution.

16+k+14+k+16=1

k=524

Now,

xi Px=xi xiPxi xi2Pxi
-2 16 -13 23
-1 k -k k
0 14 0 0
1 k k k
2 16 13 23
    xiPxi=0 xi2Pxi=43+2k

Variance=xi2Pxi-xiPxi2.

                 =43+2k-0

                   =43+2×524

                    =74

Asked in: AP EAMCET 2018 (25 Apr Shift 1)

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