Math Problem Statement
A nurse has found that when a patient calls the medical advice line claiming to have the flu, the chance that he or she truly has the flu (and not just a nasty cold) is only about 16%. Of the next 30 patients calling in claiming to have the flu, we are interested in how many actually have the flu.
Let the random variable X be the number of patients, out of the 30 who called the medical help line, that actually have the flu. How is X distributed?
Correct CorrectCorrect Part 3 of 3 Find the probability that exactly 4 of the 30 patients actually have the flu.
Find the probability that fewer than 8 of the 30 patients actually have the flu.
Solution
This problem deals with binomial distribution because each patient call is an independent event with only two possible outcomes: the patient either has the flu or doesn't have the flu. We can define the situation using the following parameters:
- is the random variable representing the number of patients (out of 30) that actually have the flu.
- Each patient has a 16% chance of having the flu, so the probability of success () is 0.16.
- There are patients who call, and we want to find probabilities for specific values of .
The distribution of can be described as:
1. Finding the probability that exactly 4 of the 30 patients actually have the flu:
We use the binomial probability formula to find this probability. The formula is:
Where:
- ,
- (since we are looking for the probability that exactly 4 patients have the flu),
- , and
- .
Let's calculate .
2. Finding the probability that fewer than 8 patients actually have the flu:
Here, we need to calculate , which is the cumulative probability of taking values from 0 to 7. This can be calculated as:
We can compute this cumulative probability directly. I'll calculate both now.1. The probability that exactly 4 of the 30 patients actually have the flu is approximately 0.193 (or 19.3%).
- The probability that fewer than 8 of the 30 patients actually have the flu is approximately 0.905 (or 90.5%).
Would you like more details on how these calculations are done, or do you have any other questions?
Here are 5 related questions that expand on this information:
- What is the probability that none of the 30 patients actually have the flu?
- What is the expected number of patients who actually have the flu out of 30?
- How would the probabilities change if the probability of having the flu increased to 25%?
- What is the probability that more than 10 of the 30 patients actually have the flu?
- Can we approximate this binomial distribution with a normal distribution? If so, how?
Tip: For large sample sizes, binomial distributions can often be approximated by a normal distribution, which simplifies calculations.
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Math Problem Analysis
Mathematical Concepts
Binomial Distribution
Probability
Formulas
P(X = k) = (n choose k) * p^k * (1 - p)^(n - k)
P(X < 8) = P(X = 0) + P(X = 1) + ... + P(X = 7)
Theorems
Binomial Probability Theorem
Suitable Grade Level
Grades 10-12
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