Math Problem Statement

In IQ test was given to a simple random sample of 76 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of σ = 10. It is desired to construct a 90% confidence interval for the mean IQ score of students at this college.

Solution

To find the standard error (Part 3 of 6) in this scenario, we use the formula:

Standard Error=σn\text{Standard Error} = \frac{\sigma}{\sqrt{n}}

where:

  • σ=10\sigma = 10 (the population standard deviation),
  • n=76n = 76 (the sample size).

Calculation:

Standard Error=1076108.71781.1456\text{Standard Error} = \frac{10}{\sqrt{76}} \approx \frac{10}{8.7178} \approx 1.1456

So, the standard error, rounded to four decimal places, is 1.1456.

Would you like further details or have any questions?


Related Questions:

  1. What is the formula for constructing a confidence interval for the mean?
  2. Why is a critical value of 1.645 used for a 90% confidence level?
  3. How would the standard error change with a larger sample size?
  4. How does knowing the population standard deviation (as opposed to the sample) impact the calculation?
  5. What would be the steps if you were calculating a 95% confidence interval instead?

Tip:

Remember, the standard error decreases as the sample size increases, improving the precision of your confidence interval.

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Math Problem Analysis

Mathematical Concepts

Statistics
Confidence Intervals
Standard Error

Formulas

Point Estimate = Sample Mean
Standard Error = σ / √n
Confidence Interval = Point Estimate ± (Critical Value * Standard Error)

Theorems

Central Limit Theorem

Suitable Grade Level

Undergraduate (Introductory Statistics)