Math Problem Statement

A population of values has an unknown distribution with a mean (μ) of 22.6 and a standard deviation (σ) of 29.4. You intend to draw a random sample of size n = 86. What is the mean of the distribution of sample means? What is the standard deviation of the distribution of sample means?

Solution

Let's go through the problem step-by-step.

  1. Mean of the distribution of sample means (μxˉ\mu_{\bar{x}}):

    The mean of the distribution of sample means is the same as the population mean (μ\mu). μxˉ=μ=22.6\mu_{\bar{x}} = \mu = 22.6 So, μxˉ=22.6\mu_{\bar{x}} = 22.6.

  2. Standard deviation of the distribution of sample means (σxˉ\sigma_{\bar{x}}):

    The standard deviation of the sample means, also called the standard error, is calculated using the formula: σxˉ=σn\sigma_{\bar{x}} = \frac{\sigma}{\sqrt{n}} where:

    • σ=29.4\sigma = 29.4 (population standard deviation)
    • n=86n = 86 (sample size)

    Plugging in the values: σxˉ=29.48629.49.27363.17\sigma_{\bar{x}} = \frac{29.4}{\sqrt{86}} \approx \frac{29.4}{9.2736} \approx 3.17

    So, σxˉ3.17\sigma_{\bar{x}} \approx 3.17.

Final Answers:

  1. μxˉ=22.6\mu_{\bar{x}} = 22.6
  2. σxˉ3.17\sigma_{\bar{x}} \approx 3.17

Would you like any further explanation on these concepts?

Here are 5 related questions to deepen your understanding:

  1. What is the significance of the Central Limit Theorem in relation to the distribution of sample means?
  2. How does increasing the sample size affect the standard error?
  3. If the population distribution were normal, how would that influence the sample mean distribution?
  4. What happens to the mean and standard error if the population mean changes but the sample size remains constant?
  5. How would you calculate a confidence interval for the sample mean in this case?

Tip: Remember that as sample size increases, the standard error decreases, meaning the sample mean becomes a more accurate estimate of the population mean!

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Math Problem Analysis

Mathematical Concepts

Statistics
Sampling Distribution
Standard Error

Formulas

Mean of sample means: μₓ̄ = μ
Standard error: σₓ̄ = σ / √n

Theorems

Central Limit Theorem

Suitable Grade Level

College Level Statistics