Answer:
Given information:
Let's define the following:
n = number of trials (number of adult smartphone users selected) = 9
p = probability of success (using the smartphone in meetings or classes) = 0.59
q = probability of failure (not using the smartphone in meetings or classes) = 1 - p = 1 - 0.59 = 0.41
x = number of successes (number of adult smartphone users using their phones in meetings or classes)
The probability of getting exactly x successes in n trials is given by the binomial probability mass function:
P(X = x) = (n choose x) * p^x * q^(n-x)
We want to find the probability of getting at least 4 successes, so we need to calculate the sum of the probabilities for x = 4, 5, 6, 7, 8, and 9.
P(X ≥ 4) = P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9)
Using the binomial probability mass function and a calculator or a programming language, we can compute the individual probabilities and sum them up.
P(X ≥ 4) = (9 choose 4) * 0.59^4 * 0.41^5 + (9 choose 5) * 0.59^5 * 0.41^4 + (9 choose 6) * 0.59^6 * 0.41^3 + (9 choose 7) * 0.59^7 * 0.41^2 + (9 choose 8) * 0.59^8 * 0.41^1 + (9 choose 9) * 0.59^9 * 0.41^0
After calculating the individual probabilities and summing them up, we get:
P(X ≥ 4) ≈ 0.8956 or 89.56%
Therefore, the probability that at least 4 out of 9 randomly selected adult smartphone users use their smartphones in meetings or classes is approximately 89.56%.
Step-by-step explanation:
