Mark (√) against the correct answer in each of the following:
A coin is tossed 5 times. What is the probability that the head appears an even number of times?
Using Bernoulli’s Trial P(Success=x) = nCx.px.q(n-x)
x=0, 1, 2, ………n and q = (1-p)
As the coin is tossed 5 times the total number of outcomes will be 
.
And we know that the favourable outcomes of getting the head even number of times ,successes will be, getting a head,
The probability of success is 
and of failure is also 
the probability that head appears an even number of times =
P(0)+P(2)+P(4)
= 5C2(
)2(
)3 +5C3(
)3(
)2 +5C5 (
)5(
)0
⇒ 
1