A coin is tossed 5 times. The probability of head is . The probability of exactly 2 heads is

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Answer (Detailed Solution Below)

Option 3 :

Detailed Solution

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Concept:

Binomial distribution:

It gives the probability of happening of event 'r' times exactly in 'n' trials.

P(r) = nCr(p)r(q)n - r

where n = number of trials, r = number of favourable events, p = probability of happening of an event and q = (1 - p) probability of not happening of an event.

Calculation:

Given:

n = 5 (tossed 5 times), r = 2 (exactly two heads), p = 1/2 (probability of happening event) and q = 1/2 (probability of not happening of an event)

P(r) = nCr(p)r(q)n - r

∴ probability of head occurring exactly 2 times is P(2).

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