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MHT CET202122 Sep 2021Evening ShiftMathematicsProbabilityActual

If the mean and variance of a binomial distribution are 4 and 2 respectively, then probability of getting 2 heads is

Options

  1. A28 256
  2. B37 256
  3. C128 256
  4. D219 256

Correct answer

A. 28 256

Step-by-step solution

We have n p=4 and n p q=2 q = 2 4 = 1 2 p =1- 1 2 = 1 2 and n ( 1 2 )=4 n =8 P(x=2)= ^8 C₂ ( 1 2 )^2 ( 1 2 )^6= 8 ! 2 ! 6 ! ( 1 2 )^8= 8 7 2 2^3 2^5 = 7 64 = 28 256

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