Math Problem Statement

A population of values has a normal distribution with μ = 129.7 and σ = 91.3. You intend to draw a random sample of size n = 147. What is the mean of the distribution of sample means? What is the standard deviation of the distribution of sample means?

Solution

This question is related to the Central Limit Theorem (CLT). Let's break it down:

Given:

  • Population mean (μ\mu) = 129.7
  • Population standard deviation (σ\sigma) = 91.3
  • Sample size (nn) = 147

Questions:

  1. What is the mean of the distribution of sample means?

    • The mean of the sample means (μxˉ\mu_{\bar{x}}) is the same as the population mean (μ\mu).
    • So, μxˉ=129.7\mu_{\bar{x}} = 129.7.
  2. What is the standard deviation of the distribution of sample means (also known as the standard error)?

    • The standard deviation of the sample means (standard error, σxˉ\sigma_{\bar{x}}) is calculated by: σxˉ=σn\sigma_{\bar{x}} = \frac{\sigma}{\sqrt{n}} Substituting the values: σxˉ=91.3147=91.312.1247.53\sigma_{\bar{x}} = \frac{91.3}{\sqrt{147}} = \frac{91.3}{12.124} \approx 7.53 So, the standard deviation of the sample means is approximately 7.53.

Final Answers:

  • μxˉ=129.7\mu_{\bar{x}} = 129.7
  • σxˉ7.53\sigma_{\bar{x}} \approx 7.53

Would you like further clarification or details on these calculations?

Here are 5 follow-up questions to consider:

  1. How does increasing the sample size affect the standard deviation of sample means?
  2. What is the importance of the Central Limit Theorem in statistics?
  3. Can the Central Limit Theorem be applied to non-normal populations? Why?
  4. How would the standard error change if the sample size were halved?
  5. What is the significance of a smaller standard error in terms of sample accuracy?

Tip: The Central Limit Theorem states that the distribution of sample means approaches normality as the sample size increases, regardless of the population's distribution.

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Math Problem Analysis

Mathematical Concepts

Statistics
Central Limit Theorem
Normal Distribution
Standard Error

Formulas

Mean of sample means: μ_x̄ = μ
Standard deviation of sample means (Standard Error): σ_x̄ = σ / √n

Theorems

Central Limit Theorem

Suitable Grade Level

Undergraduate