Math Problem Statement

Information from the American Institute of Insurance indicates the mean amount of life insurance per household in the United States is $104,000. This distribution follows the normal distribution with a standard deviation of $31,000.

Required: If we select a random sample of 42 households, what is the standard error of the mean? Note: Round your answer to the nearest whole number.

Solution

To calculate the standard error of the mean (SExˉSE_{\bar{x}}), we use the formula:

SExˉ=σnSE_{\bar{x}} = \frac{\sigma}{\sqrt{n}}

Where:

  • σ=31,000\sigma = 31,000 (the standard deviation),
  • n=42n = 42 (the sample size).

Let's compute this.

SExˉ=31,00042SE_{\bar{x}} = \frac{31,000}{\sqrt{42}}The standard error of the mean for a sample of 42 households is approximately 4,783.

Would you like any further details or clarifications?

Here are five related questions:

  1. How does sample size affect the standard error of the mean?
  2. What does the standard error of the mean represent in the context of sampling?
  3. How would the result change if the sample size increased to 100 households?
  4. Why is the normal distribution assumption important in this problem?
  5. How is the standard error different from the standard deviation?

Tip: A larger sample size generally reduces the standard error, providing a more precise estimate of the population mean.

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Math Problem Analysis

Mathematical Concepts

Statistics
Sampling Distribution
Standard Error

Formulas

Standard error of the mean: SE = σ / √n

Theorems

Central Limit Theorem

Suitable Grade Level

Grades 10-12