Math Problem Statement

The scores on a standardized test taken at the University of Virginia are normally distributed with a mean of 95 and a standard deviation of 15. What test score is 1.9 standard deviations below the mean?

Solution

The question asks for a test score that is 1.9 standard deviations below the mean for a normally distributed set of test scores.

Given:

  • Mean (μ\mu) = 95
  • Standard deviation (σ\sigma) = 15
  • Distance from the mean = 1.9 standard deviations below

To calculate the test score:

Score=μ(1.9×σ)\text{Score} = \mu - (1.9 \times \sigma)

Substituting the given values:

Score=95(1.9×15)\text{Score} = 95 - (1.9 \times 15) Score=9528.5=66.5\text{Score} = 95 - 28.5 = 66.5

Thus, the test score that is 1.9 standard deviations below the mean is 66.5.

Would you like more details or have any other questions?

Here are 5 related questions to explore:

  1. What is the test score 2.5 standard deviations above the mean?
  2. How do you find the probability of scoring below a certain value in a normal distribution?
  3. What percentage of scores falls between one standard deviation above and below the mean?
  4. How do you standardize a score (convert to a z-score)?
  5. If the standard deviation changes, how does it affect the spread of the distribution?

Tip: To calculate how far a value is from the mean, multiply the number of standard deviations by the standard deviation itself.

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Math Problem Analysis

Mathematical Concepts

Normal Distribution
Standard Deviation
Z-Score

Formulas

Score = Mean - (Z-Score × Standard Deviation)

Theorems

Properties of Normal Distribution

Suitable Grade Level

Grades 10-12