Math Problem Statement

Suppose that 100 items are drawn from a population of manufactured products and the weight, X, of each item is recorded. Prior experience has shown that the weight has a non- normal probability distribution with u - 3 ounces. Which of the following is true about the sampling of X? = 8 ounces and o a. Its mean is 8 ounces b. Its standard error is 0.3 ounces. c. Its shape is approximately normal d. All of these choices are true.

Solution

Given the scenario, let's break down each option:

  1. Option (a): Its mean is 8 ounces.

    • This statement implies that the mean weight of the sampled items is 8 ounces. If the mean of the population is μ=8\mu = 8 ounces, then the mean of the sample (Xˉ\bar{X}) will also be approximately 8 ounces by the law of large numbers.
  2. Option (b): Its standard error is 0.3 ounces.

    • The standard error (SE) of the sample mean Xˉ\bar{X} is calculated using the formula: SE=σn\text{SE} = \frac{\sigma}{\sqrt{n}} Where σ\sigma is the population standard deviation, and nn is the sample size. Given σ=3\sigma = 3 ounces and n=100n = 100, the SE would be: SE=3100=310=0.3 ounces\text{SE} = \frac{3}{\sqrt{100}} = \frac{3}{10} = 0.3 \text{ ounces} So, this statement is true.
  3. Option (c): Its shape is approximately normal.

    • The Central Limit Theorem (CLT) states that the sampling distribution of the sample mean Xˉ\bar{X} will be approximately normal, regardless of the shape of the population distribution, provided the sample size is large enough. In this case, with a sample size of 100, the distribution of Xˉ\bar{X} should be approximately normal.
  4. Option (d): All of these choices are true.

    • Since options (a), (b), and (c) are all true, this option is also correct.

Conclusion: (d) All of these choices are true is the correct answer.

Would you like more details or have any questions?


Here are some related questions to consider:

  1. What is the Central Limit Theorem, and why is it important?
  2. How does the sample size affect the standard error?
  3. Why is the normality of the sampling distribution important in statistical inference?
  4. What would happen to the standard error if the sample size was reduced to 25?
  5. How can the law of large numbers be explained in the context of this problem?
  6. What would the implications be if the population standard deviation σ\sigma were unknown?
  7. How would you calculate a confidence interval for the mean weight based on the sample?
  8. What assumptions must hold true for the Central Limit Theorem to apply?

Tip: When working with sampling distributions, always check whether the sample size is large enough for the Central Limit Theorem to ensure the normality of the sampling distribution.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Probability
Sampling
Central Limit Theorem

Formulas

Standard Error formula: SE = σ / sqrt(n)

Theorems

Central Limit Theorem
Law of Large Numbers

Suitable Grade Level

Undergraduate level