SATMediumFrequency: 1 - 2 questions
Standard Deviation, Range, and Box Plot Comparisons
Standard deviation measures how spread out values are from the mean. A dataset where values are clustered tightly around the center has a smaller standard deviation than one with values scattered across the extremes.
Core Formula & Concept Cheat Sheet
1Standard deviation = Spread/dispersion of data from mean
2Adding a constant to every data point DOES NOT change standard deviation or range
3Outliers dramatically affect the mean and range, but have little effect on median and IQR.
The 700+ Score Trap
Thinking that higher values or larger sums mean larger standard deviation (standard deviation only measures spread, not magnitude).
Test Your Mastery
Official Exam FormatLive Interactive Practice Drill
Dataset A: {10, 10, 10, 10, 10}
Dataset B: {2, 6, 10, 14, 18}
Which statement correctly compares the standard deviations of the two datasets?
Frequently Asked Questions
If I add 10 to every score on a test, what happens to standard deviation?
Standard deviation remains completely unchanged because the spread between data points is identical.