SOLUTION: a research organization decides to mail 9 questionnaires to people selected at random. if the probability of anyone answering the questionnaire is 1/7 find the probability that exa

Question 1102738: a research organization decides to mail 9 questionnaires to people selected at random. if the probability of anyone answering the questionnaire is 1/7 find the probability that exactly 5 will answer the questionnaire
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
It is 9C5(1/7)^5(6/7)^4, the 9C5 being the number of ways 5 people out of 9 can answer.
126*(1/7)^5(6/7)^4
126*1296/7^9=126*1296/40353607=0.0040. ANSWER
The expected value is 9/7, so it is very unlikely.
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