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Prince Edward Island Fisheries and Environment has been feeding a special food to rainbow trout fingerlings in a pond. A sample of the weights of 36 trout revealed that the mean weight is 402.7 grams and the standard deviation 8.8 grams. What is the probability that the mean weight for a sample of 40 trout exceeds 405.5 grams?

A. 0.3783
B. 0.0222
C. 1.0
D. 0.0281

User Lostlogic
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1 Answer

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Final answer:

To find the probability that the mean weight for a sample of 40 trout exceeds 405.5 grams, we can use the Central Limit Theorem. According to the Central Limit Theorem, if we have a large enough sample size, the sampling distribution of the sample mean will be approximately normal, regardless of the shape of the population distribution. The probability that the mean weight for a sample of 40 trout exceeds 405.5 grams is approximately 0.0257.

Step-by-step explanation:

To find the probability that the mean weight for a sample of 40 trout exceeds 405.5 grams, we can use the Central Limit Theorem. According to the Central Limit Theorem, if we have a large enough sample size, the sampling distribution of the sample mean will be approximately normal, regardless of the shape of the population distribution.

In this case, the sample size is 40, which is reasonably large. So we can assume that the sampling distribution of the sample mean will be approximately normal. The mean weight for the sample of 40 trout can be calculated as follows:

mean = mean of the population = 402.7 grams

The standard deviation of the sample mean can be calculated using the formula:

standard deviation = standard deviation of the population / sqrt(sample size)

Substituting the values, we get:

standard deviation = 8.8 grams / sqrt(40)

Now, we can convert the problem into a standard normal distribution problem by using the formula:

Z = (x - mean) / standard deviation

Substituting the values, we get:

Z = (405.5 - 402.7) / (8.8 / sqrt(40))

Calculating the value of Z, we find:

Z = 1.97

The area to the right of Z = 1.97 in the standard normal distribution is approximately 0.0257. Therefore, the probability that the mean weight for a sample of 40 trout exceeds 405.5 grams is approximately 0.0257.

User Dkong
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