Math Problem Statement

When asked, "Do kids regularly carry weapons in your school?" 14,255 students said yes, and 115,335 students said no. With a 95% level of confidence, find the margin of error (MOE) associated with the sample proportions. (Give the answer to one decimal place, if needed.) MOE

Solution

To calculate the margin of error (MOE) for the given proportions at a 95% confidence level, we use the formula:

MOE=Zα/2×p(1p)nMOE = Z_{\alpha/2} \times \sqrt{\frac{p(1 - p)}{n}}

Where:

  • Zα/2Z_{\alpha/2} is the critical value from the standard normal distribution for a 95% confidence level, which is approximately 1.96.
  • pp is the sample proportion of students who answered "yes."
  • nn is the total sample size.

Step 1: Find the sample proportion pp

The total number of students surveyed is: n=14,255+115,335=129,590n = 14,255 + 115,335 = 129,590 The proportion of students who answered "yes" is: p=14,255129,5900.1100p = \frac{14,255}{129,590} \approx 0.1100

Step 2: Apply the formula

Now, we substitute pp, nn, and Zα/2Z_{\alpha/2} into the MOE formula: MOE=1.96×0.1100(10.1100)129,590MOE = 1.96 \times \sqrt{\frac{0.1100(1 - 0.1100)}{129,590}} Let’s calculate this.

The margin of error (MOE) for the sample proportions at a 95% confidence level is approximately 0.0017, or 0.17%.

Would you like further details or have any questions?

Here are five related questions:

  1. How does the confidence level affect the margin of error?
  2. What happens to the MOE if the sample size increases?
  3. Can the margin of error be negative?
  4. How would the MOE change if the confidence level were 99% instead of 95%?
  5. What is the difference between margin of error and standard error?

Tip: Larger sample sizes generally reduce the margin of error, making estimates more precise.

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Math Problem Analysis

Mathematical Concepts

Statistics
Confidence Intervals
Sample Proportions

Formulas

MOE = Z_alpha/2 * sqrt((p(1-p))/n)

Theorems

Central Limit Theorem
Properties of Proportions

Suitable Grade Level

Grades 10-12 (Advanced High School), College-Level Intro Statistics