The binomial distribution is given by,
P(X=x) =
q = probability of failure = 1-0.2 = 0.8
n = 100
They have asked to find the probability <span>of obtaining a score less than or equal to 12.
</span>∴ P(X≤12) =
where, x = 0,1,2,3,4,5,6,7,8,9,10,11,12
∴ P(X≤12) =
+ 
+ 
+ 
+ 
+ 
+ 
Evaluating each term and adding them you will get,
P(X≤12) = 0.02532833572
This is the required probability.
P(X=x) =
q = probability of failure = 1-0.2 = 0.8
n = 100
They have asked to find the probability <span>of obtaining a score less than or equal to 12.
</span>∴ P(X≤12) =
where, x = 0,1,2,3,4,5,6,7,8,9,10,11,12
∴ P(X≤12) =
Evaluating each term and adding them you will get,
P(X≤12) = 0.02532833572
This is the required probability.