Mark (√) against the correct answer in each of the following:
The probability that an event E occurs in one trial is 0.4, Three independent trials of the experiment are performed. What is the probability that E occurs at least once?
The probability of occurrence of an event E in one trial is 0.4
Using Bernoulli’s Trial we have,
P(Success=x) = nCx.px.q(n-x)
x=0, 1, 2, ………n and q = (1-p), n =3
p = 0.4 , q = 0.6
The probability that E occurs at least once is,
P(1)+P(2)+P(3)
⇒ 3C1(
)1(
)2+3C2(
)2(
)1+3C3(
)3(
)0
⇒ 
1