Mark (√) against the correct answer in each of the following:
In 4 throws of a pair of dice, what is the probability of throwing doublets at least twice?
Using Bernoulli’s Trial P(Success=x) = nCx.px.q(n-x)
x=0, 1, 2, ………n and q = (1-p)
As we know that the favourable outcomes of getting at least doublets twice are, successes will be, getting a doublet, i.e.,
, p = 
,q = 
The probability of success is 
and of failure is also 
the probability of getting at least 2 successes =
P(2)+P(3)+P(4)
⇒ 4C2(
)2(
)2 +4C3(
)3(
)1+4C4(
)4(
)0
⇒ 
1