According to one study, 61% of the population swallow at least one spider per year in their sleep.

Question

Based on this study, what is the probability that exactly 7 of 10 randomly selected people have
swallowed at least one spider in their sleep in the last year? (1 point)

70%

34%

1%

22%

Answer 1

The probability can be calculated using the binomial probability formula: P(x) = (n choose x) * p^x * (1-p)^(n-x)

In this case, n = 10 (number of randomly selected people), x = 7 (number of people who have swallowed at least one spider), p = 0.61 (probability of an individual swallowing at least one spider).

P(7) = (10 choose 7) * 0.61^7 * (1-0.61)^(10-7)
P(7) = (10! / (7!(10-7)!) * 0.61^7 * 0.39^3
P(7) = (120) * 0.0029 * 0.07539
P(7) = 0.26253

Therefore, the probability that exactly 7 out of 10 randomly selected people have swallowed at least one spider in the last year is approximately 26.25%.

Therefore, the closest answer choice is 22% which is the answer.

Correct Answer: 22%