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
Median
Problem 3.r.1h
Textbook Question
Reported and Measured Heights Listed below are self-reported heights of males aged 16 and over and their corresponding measured heights (based on data from the National Health and Nutrition Examination Survey). All heights are in inches. First find the differences (reported height–measured height), and then use those differences to find the (h) Q1, (i) Q3


1
Step 1: Calculate the differences between the reported heights and the measured heights for each individual. Use the formula: Difference = Reported Height - Measured Height. For example, for the first individual, the difference is 68.0 - 67.9 = 0.1.
Step 2: List all the calculated differences in a new dataset. For example, the differences for the given data will be a list of values corresponding to each pair of reported and measured heights.
Step 3: Arrange the differences in ascending order. This step is necessary to calculate the quartiles (Q1 and Q3).
Step 4: Identify Q1 (the first quartile) by finding the value at the 25th percentile of the ordered differences. If the dataset size is not a multiple of 4, interpolate between the nearest ranks.
Step 5: Identify Q3 (the third quartile) by finding the value at the 75th percentile of the ordered differences. Again, interpolate if necessary to determine the exact value.

This video solution was recommended by our tutors as helpful for the problem above
Video duration:
3mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Differences Calculation
To analyze the self-reported and measured heights, one must first calculate the differences between the reported and measured values. This is done by subtracting the measured height from the reported height for each individual. These differences will help in understanding the accuracy of self-reported data and are essential for further statistical analysis.
Recommended video:
Guided course
Find 5-Number Summary - TI-84 Calculator
Quartiles
Quartiles are statistical measures that divide a dataset into four equal parts, providing insights into the distribution of data. The first quartile (Q1) represents the 25th percentile, while the third quartile (Q3) represents the 75th percentile. Calculating Q1 and Q3 from the differences will help identify the spread and central tendency of the discrepancies between reported and measured heights.
Recommended video:
Guided course
Find 5-Number Summary - TI-84 Calculator
Data Interpretation
Data interpretation involves analyzing the calculated differences and quartiles to draw conclusions about the self-reported heights. Understanding how these differences vary can reveal patterns, such as whether individuals tend to overestimate or underestimate their heights. This analysis is crucial for assessing the reliability of self-reported data in health surveys.
Recommended video:
Guided course
Visualizing Qualitative vs. Quantitative Data
Watch next
Master Calculating the Median with a bite sized video explanation from Patrick
Start learning