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If the true proportion of customers who are below 20 years is P=0.35, what is the probability that a sample size of 100 yields a sample proportion between 0.3 to 0.4 0.961 0.827 0.706 0.53

Question

If the true proportion of customers who are below 20 years is P=0.35, what is the probability that a sample size of 100 yields a sample proportion between 0.3 to 0.4 0.961 0.827 0.706 0.53

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Solution

The question seems to be asking for the probability that a sample proportion falls between 0.3 and 0.4 given a true population proportion of 0.35. This is a question of sampling distributions and can be solved using the Central Limit Theorem (CLT) which states that the sampling distribution of the sample mean approaches a normal distribution as the sample size gets larger, regardless of the shape of the population distribution.

Here are the steps to solve this problem:

  1. First, we need to find the standard deviation of the sampling distribution. The standard deviation (σp̂) of the sampling distribution of the proportion is calculated as:

    σp̂ = sqrt [ P(1 - P) / n ]

    where P is the population proportion (0.35 in this case), and n is the sample size (100 in this case).

  2. Next, we need to standardize the sample proportions (0.3 and 0.4) using the following formula:

    Z = (p̂ - P) / σp̂

    where p̂ is the sample proportion, P is the population proportion, and σp̂ is the standard deviation of the sampling distribution.

  3. Once we have the Z-scores for the sample proportions, we can find the corresponding probabilities from the standard normal distribution table or using a calculator with a normal distribution function.

  4. The probability that the sample proportion is between 0.3 and 0.4 is the probability corresponding to the Z-score for 0.4 minus the probability corresponding to the Z-score for 0.3.

Without the actual calculations, I can't tell you which of the provided options (0.961, 0.827, 0.706, 0.53) is correct. But these are the steps you would follow to solve this problem.

This problem has been solved

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