Range
Topic: Economic Data: Census, NSS, Surveys and Statistical Tools · NCERT: Class 11, Ch 2 "Collection of Data"; Class 11, Ch 3 "Organisation of Data"; Class 11, Ch 8 "Use of Statistical Tools"
Meaning
The range is the gap between the largest and the smallest value of a variable. Range = largest value − smallest value When organising data, the range helps decide how many classes to make and how wide they should be. Number of classes = range ÷ class width. Usually a table has 6 to 15 classes. The range is also the simplest measure of dispersion, meaning a measure of how spread out the data are. But it looks only at the two extreme values and ignores everything in between.
Example
In NCERT's data, the monthly food spending of 50 households runs from Rs 1,007 to Rs 5,090. The range is Rs 4,083. With a class width of Rs 500, this needs about 9 classes (4,083 ÷ 500 ≈ 8.2, rounded up).
Don't confuse with
- Class interval: this is the width of one class (upper limit − lower limit). The range covers the whole data set.
Related concepts
- Raw data
- Classification
- Chronological classification
- Spatial classification
- Qualitative classification
- Quantitative classification
- Attribute
- Continuous variable
- Discrete variable
- Frequency