Table of contents
- 1. Intro to Stats and Collecting Data55m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically1h 45m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables2h 33m
- 6. Normal Distribution and Continuous Random Variables1h 38m
- 7. Sampling Distributions & Confidence Intervals: Mean1h 3m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 12m
- 9. Hypothesis Testing for One Sample1h 1m
- 10. Hypothesis Testing for Two Samples2h 8m
- 11. Correlation48m
- 12. Regression1h 4m
- 13. Chi-Square Tests & Goodness of Fit1h 20m
- 14. ANOVA1h 0m
3. Describing Data Numerically
Interpreting Standard Deviation
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
A sample of 500 random adult books in a library has an average of 312 pages with a standard deviation of 26 pages. According to the Empirical Rule of Standard Deviation, find the central range of page lengths containing 95% of the books in the sample.
A
B
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D

1
Identify the key components of the problem: the sample mean (312 pages), the standard deviation (26 pages), and the percentage of data to be covered (95%). The Empirical Rule states that 95% of the data falls within 2 standard deviations from the mean in a normal distribution.
Calculate the lower bound of the range by subtracting 2 standard deviations from the mean. Use the formula: Lower Bound = Mean - 2 × Standard Deviation. In MathML:
Calculate the upper bound of the range by adding 2 standard deviations to the mean. Use the formula: Upper Bound = Mean + 2 × Standard Deviation. In MathML:
Combine the lower and upper bounds to form the central range. This range represents the page lengths containing 95% of the books in the sample.
Verify the calculated range against the provided options to identify the correct answer. The correct range should match the interval (260, 364).
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