The Q-Q Plot, A Graphical Method for Comparing Two Samples (UMAP)

This module presents a graphical method that is useful for displaying and comparing two sets of data. This method displays the information from both samples in a single plot, and it permits clear and easy comparison of many different aspects of two sets of measurements.

Table of Contents:

1. EXPLAINING THE Q-Q PLOT

2. INTERPRETATION WHEN BOTH SAMPLES ARE THE SAME

3. INTERPRETATIONS WHEN THE SAMPLES DIFFER IN LOCATION (MEDIAN)

4. INTERPRETATION WHEN THE SAMPLES DIFFER IN VARIABILITY (INTERQUARTILE RANGE)

5. INTERPRETATION OF EXTREME VALUES--TAILS

6. INTERPRETATION WHEN THE POINTS DO NOT FALL ON A STRAIGHT LINE--SHAPE

7. INTERPRETATION OF THE BATTERY EXAMPLE Q-Q PLOT

8. Q-Q PLOT WITH UNEQUAL SAMPLE SIZES

9. CONCLUDING COMMENTS ON Q-Q PLOTS

10. SOLUTIONS TO EXERCISES