TargetIIT

1)the mean and the variance of a binomial distribution are 4 and 2 respectively.then probability of 2 successes is
a)37/256
b)219/256
c)128/256
d)28/256

2)n persons sit on a round table. the odd two against two specified persons sitting together is
a)2:n-3
b)n-1:2
c)n-2:2
d)n-3:2

1<.d>
np=4        npq=2

p=q=0.5...............as p+q=1

n=8.....
P(2)= 8C2*(.5)[p]2[/p](.5)[p]6[/p]=(d)