Question

According to the 2003 National Survey on Drug Use and Health, 55.3% of males have never used marijuana. Based on this percentage, what is the probability that more than 50 males who have used marijuana for samples of size 120 ? Select one: a. 0.8921 b. 0.717 c. 0.0018 d. 0.0010 The correct answer is: 0.717

Answer 1

To find the probability that more than 50 males who have used marijuana are selected from a sample of size 120, we use the binomial distribution formula. The probability is approximately 0.717.

Step-by-step explanation:

To find the probability that more than 50 males who have used marijuana are selected from a sample of size 120, we need to use the binomial distribution formula.

The formula for the probability of getting x successes in n trials is:

P(x) = C(n, x) * px * (1-p)n-x

In this case, the probability of a male not using marijuana is 55.3%, so the probability of a male using marijuana is 100% - 55.3% = 44.7%.

We want to find the probability of more than 50 males using marijuana, so we need to calculate the sum of the probabilities of 51, 52, 53, ..., 120 males using marijuana.

Using a statistical software or a calculator, the probability comes out to be approximately 0.717.