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Houseflies have pretty short lifespans. Males of a certain species have lifespans that are strongly skewed to the

right with a mean of 26 days and a standard deviation of 12 days. A biologist collects a random sample of 9 of


these male houseflies and observes them to calculate the sample mean lifespan.


What is the probability that the mean lifespan from the sample of 9 houseflies 2 is less than 24 days?

User Dieki
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2 Answers

4 votes

Final answer:

The probability that the mean lifespan from a sample of 9 houseflies is less than 24 days is approximately 0.3085 or 30.85%.

Step-by-step explanation:

This problem involves finding the probability that the mean lifespan from a sample of 9 houseflies is less than 24 days. Since we have the population mean and standard deviation, we can use the z-score formula to standardize the sample mean. The z-score is calculated as (sample mean - population mean) / (population standard deviation / sqrt(sample size)). Once we have the z-score, we can use a standard normal distribution table to find the probability.

Substituting the given values into the formula, we get (24 - 26) / (12 / sqrt(9)) = -2 / 4 = -0.5. Looking up the z-score -0.5 in the standard normal distribution table, we find the probability to be approximately 0.3085 or 30.85%.

User Rawling
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4.8k points
6 votes

Answer: We cannot calculate this probability because the sampling distribution is not normal

Step-by-step explanation:

it’s the correct answer.

User Prasanjit Dey
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5.4k points