Frequency
Topic: Economic Data: Census, NSS, Surveys and Statistical Tools · NCERT: Class 11, Ch 3 "Organisation of Data"; Class 11, Ch 8 "Use of Statistical Tools"
Meaning
Frequency is the number of times a value occurs in the data. In a frequency distribution, it is the number of observations in a class, called the class frequency. Frequency shows how the data are spread across values or classes. It is the basis for frequency tables, histograms and ogives.
Example
In NCERT's maths marks data for 100 students, 21 students scored in the 40-50 class, so that class has a frequency of 21. Adding the frequencies of all ten classes gives the total of 100 students.
Don't confuse with
- Cumulative frequency: a running total of frequencies up to or beyond a class, not the count for one value or class.
Related concepts
- Raw data
- Classification
- Chronological classification
- Spatial classification
- Qualitative classification
- Quantitative classification
- Attribute
- Continuous variable
- Discrete variable
- Frequency distribution