Math Problem Statement

A population of values has a normal distribution with μ = 195.1 and σ = 77.4. You intend to draw a random sample of size n = 107. What is the mean of the distribution of sample means? What is the standard deviation of the distribution of sample means?

Solution

In the image, you are asked to solve a problem related to the Central Limit Theorem. Here's a breakdown:

  1. Given Information:

    • The population has a normal distribution with:
      • Mean μ=195.1\mu = 195.1
      • Standard deviation σ=77.4\sigma = 77.4
    • Sample size n=107n = 107
  2. Questions:

    • What is the mean of the distribution of sample means?

      • According to the Central Limit Theorem, the mean of the sampling distribution of the sample means, denoted by μxˉ\mu_{\bar{x}}, is the same as the population mean: μxˉ=μ=195.1\mu_{\bar{x}} = \mu = 195.1
    • What is the standard deviation of the distribution of sample means?

      • The standard deviation of the sampling distribution of the sample means, denoted by σxˉ\sigma_{\bar{x}}, is given by the formula: σxˉ=σn=77.4107\sigma_{\bar{x}} = \frac{\sigma}{\sqrt{n}} = \frac{77.4}{\sqrt{107}} Let's calculate that: σxˉ77.410.3447.48\sigma_{\bar{x}} \approx \frac{77.4}{10.344} \approx 7.48 So, the standard deviation of the sample means is approximately 7.487.48, rounded to two decimal places as requested.

Final Answers:

  • Mean of sample means μxˉ=195.1\mu_{\bar{x}} = 195.1
  • Standard deviation of sample means σxˉ7.48\sigma_{\bar{x}} \approx 7.48

Would you like more details or have any questions? Here are 5 related questions for practice:

  1. What happens to the standard deviation of the sample means if the sample size is increased?
  2. If the sample size was 50 instead of 107, how would σxˉ\sigma_{\bar{x}} change?
  3. Explain why the Central Limit Theorem is important when the sample size is large.
  4. How does the Central Limit Theorem apply when the population is not normally distributed?
  5. Calculate σxˉ\sigma_{\bar{x}} if the population standard deviation was 9090 and the sample size was 200200.

Tip: As the sample size increases, the standard deviation of the sample means decreases, making the sample mean a more accurate estimate of the population mean.

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Math Problem Analysis

Mathematical Concepts

Central Limit Theorem
Sampling Distribution
Normal Distribution

Formulas

Mean of sample means: μ_x = μ
Standard deviation of sample means: σ_x = σ / √n

Theorems

Central Limit Theorem

Suitable Grade Level

Undergraduate