Data
Spread & quartiles
How spread out is your data? Add points, watch the box plot reshape, and see Q1, median, Q3 and IQR move.
Data
Summary
- Min
- 2
- Max
- 18
- Median
- 8
- Mean
- 8.64
- Q1
- 5.5
- Q3
- 11
- Range
- 16
- IQR
- 5.5
- Std dev
- 4.46
- Count
- 11
Two data sets can have the same average and look completely different. Spread tells you how scattered the values are around that average.
Spread, four ways
- Range — biggest minus smallest
- Quartiles — split sorted data into four equal chunks
- Interquartile range (IQR) — Q3 minus Q1, the middle 50% spread
- Standard deviation — typical distance from the mean
Try it
Data: 2, 4, 4, 4, 5, 5, 7, 9. Range?
9 − 2 = 7.
Range is fooled by one weird value. IQR and standard deviation are sturdier — they don't jump just because of one outlier.