Math Problem Statement

Consider the following sample data set of exam scores, where the sample mean is 83.5 and the sample standard deviation is 16. True or False: The data comply with Chebyshev's Rule.

Solution

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Problem Description:

You have a sample data set of exam scores, with a sample mean of 83.5 and a sample standard deviation of 16. You are asked to determine whether the data comply with Chebyshev's Rule.

Chebyshev's Rule:

Chebyshev's Rule states that for any dataset, the proportion of values that lie within kk standard deviations of the mean is at least 11k21 - \frac{1}{k^2}, where k>1k > 1.

For instance:

  • At least 75% of data lies within 2 standard deviations of the mean.
  • At least 89% of data lies within 3 standard deviations of the mean.

Steps to Solve:

  1. Calculate the interval for k=2k = 2:

    • The interval within 2 standard deviations from the mean is: Mean±2×Standard Deviation=83.5±2×16=83.5±32=[51.5,115.5]\text{Mean} \pm 2 \times \text{Standard Deviation} = 83.5 \pm 2 \times 16 = 83.5 \pm 32 = [51.5, 115.5]
  2. Count how many data points fall within this interval:

    • Look at the dataset and count the number of scores within the range [51.5,115.5][51.5, 115.5].
  3. Determine the proportion:

    • Calculate the proportion of data points within this range and compare it with 75%.

Data Set:

  • Scores: 24, 56, 68, 68, 69, 78, 80, 82, 83, 84, 86, 88, 90, 91, 91, 92, 92, 92, 92, 93, 96, 97, 97, 100.

Calculation:

  1. Interval Calculation:

    • The interval within 2 standard deviations is [51.5,115.5][51.5, 115.5].
  2. Counting Data Points:

    • The data points within the interval [51.5,115.5][51.5, 115.5] are:
      • 56, 68, 68, 69, 78, 80, 82, 83, 84, 86, 88, 90, 91, 91, 92, 92, 92, 92, 93, 96, 97, 97, 100.
    • Total count: 23 out of 24 data points.
  3. Proportion Calculation:

    • Proportion = 2324=0.9583\frac{23}{24} = 0.9583 or 95.83%.
    • Since 95.83% is greater than 75%, the data comply with Chebyshev's Rule for k=2k = 2.

Conclusion:

  • Answer: True. The data comply with Chebyshev's Rule.

Would you like any further details or explanations on this problem? Here are five related questions you might consider:

  1. What would the proportion be if we considered k=3k = 3 standard deviations?
  2. How does Chebyshev's Rule compare with the Empirical Rule?
  3. Can Chebyshev's Rule be applied to all distributions, including non-normal distributions?
  4. What are the limitations of Chebyshev's Rule in practical scenarios?
  5. How would the answer change if the sample standard deviation were different?

Tip: Chebyshev's Rule is useful for any dataset, regardless of the distribution, making it more general than rules like the Empirical Rule that assume normality.

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Math Problem Analysis

Mathematical Concepts

Statistics
Data Analysis
Chebyshev's Rule

Formulas

Proportion within k standard deviations: 1 - 1/k^2

Theorems

Chebyshev's Theorem

Suitable Grade Level

Grades 10-12