Mark the correct alternative in the following:

A fair coin is tossed 99 times. If X is the number of times heads occur, then P(X = r) is maximum when r is

Given:

n=99

p(H)=P(T)=1/2

P(x=r)= ^{n}C_{r} p^{r} q^{n-r}

P(x=r)= ^{n}C_{r} p^{n}

^{n}C_{r} =

Its maximum value is closest near n/2

Since n is an odd number, so it have two values:

i.e.

S0, r= 49,50

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