Statistics And Probability Question 444

Question: In a binomial distribution the probability of getting a success is 1/4 and standard deviation is 3, then its mean is

[EAMCET 2002]

Options:

A) 6

B) 8

C) 12

D) 10

Show Answer

Answer:

Correct Answer: C

Solution:

  •         Probability of success  $ p=\frac{1}{4} $             Probability of unsuccess  $ q=\frac{3}{4} $             Mean = np            Standard deviation =  $ \sqrt{\text{Variance }} $   
    

$ \Rightarrow $ Variance = 9
Þ $ npq=9 $
Þ $ n.,\frac{1}{4}.,\frac{3}{4}=9 $
Þ $ n=48 $ Mean $ =np $ $ =\frac{1}{4}\times 48=12 $ .