Question

The probability that a person responds to a mailed questionnaire is 0.4. What is the probability that of 25 questionnaires, more than 12 will be returned? O 0.846 O 0.154 O 0.078 O 0.922

Answer 1

we have given p=0.4 n = 25

using binomial distribution to find out the probability

$p(X=x)=\binom{n}{x}p^x(1-p)^{n-x};x=0,1,2,.......,n$

25 P(X > 12x) =Σ Σ(23)ο. 0.4(1 – 0.4) 25 - T=13

= 0.154

Ans: option B) 0.154 is correct