Probability Question 229
Question: A die is tossed twice. Getting a number greater than 4 is considered a success. Then the variance of the probability distribution of the number of successes is
[AISSE 1979]
Options:
A) $ \frac{2}{9} $
B) $ \frac{4}{9} $
C) $ \frac{1}{3} $
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
Obviously, $ p=\frac{2}{6}=\frac{1}{3}\Rightarrow q=1-\frac{1}{3}=\frac{2}{3}, $ also $ n=2. $
Therefore, variance $ =npq=2\times \frac{1}{3}\times \frac{2}{3}=\frac{4}{9}. $
BETA
