1. The probability that a randomly selected teenager studied at least once durin

Question

1. The probability that a randomly selected teenager studied at least once during a week was only 0.53. What is the probability that less than half of the students in your study group of 10 have studied in the last week? (Round your answer to two decimal places.)

2. In a large on-the-job training program, half of the participants are female and half are male. In a random sample of four participants, what is the probability that an investigator will draw at least one male?† (Round your answer to four decimal places.)P(X 1)=

3. In the exercise, X is a binomial variable with n = 5 and p = 0.6. Compute the given probability. Check your answer using technology. HINT [See Example 2.] (Round your answer to five decimal places.)P(X 4)

Explanation / Answer

Since each student is independent and there are two outcomes X no of students studying is binomial with (10,0.53)

Reqd prob = P(X>=5) = 0.6943

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Prob for a male = p = 1/2

and no of males = Y is binomial

P(Y>=1) = 1-P(Y=0) = 1-(1/2^4) = 15/16

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3) P(X>=4) = P(X=4 or 5)

= 5C4(0.6)4(0.4) + (0.6)5

= (0.6)4(2.6)

= 0.33696

Using technology:

same answer 0.33696

http://stattrek.com/online-calculator/binomial.aspx

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