Probability Question 258
Question: A die is tossed thrice. If getting a four is considered a success, then the mean and variance of the probability distribution of the number of successes are
[DSSE 1987]
Options:
A) $ \frac{1}{2},\frac{1}{12} $
B) $ \frac{1}{6},\frac{5}{12} $
C) $ \frac{5}{6},\frac{1}{2} $
D) None of these
Show Answer
Answer:
Correct Answer: D
Solution:
We are given that $ n=3, $
$ p=\frac{1}{6}, $
$ q=\frac{5}{6} $
Mean $ =np=3\times \frac{1}{6}=\frac{1}{2} $
Variance $ =nqp=3\times \frac{1}{6}\times \frac{5}{6}=\frac{5}{12}. $
BETA
