Class 11 Statistics Notes · GSEB

Quantitative and Qualitative Data

Quantitative and Qualitative Data — understand population, sample, variable characteristics, and the difference between quantitative and qualitative data. GSEB Class 11 Statistics notes.

Last updated: 2 Aug 2026

Notes

Core Statistical Concepts

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Population

A group of all the units under study is called a population.

Example

To study the standard of living of workers of a factory, the group of all the workers of the factory becomes the population.

Size of Population

The total number of units contained in the population is called the size of the population. Denoted by N.

Example

If 700 workers work in a factory, then N = 700.

Finite Population

If the total number of units of the population is finite (say N), we call it a finite population.

Example

A factory with 700 workers — this is a finite population because the count has a definite limit.

Sample

A set or group of units selected from the population on the basis of some definite criterion is called a sample. The number of units in the sample is the sample size (n).

Example

If we select 150 workers from the population of 700 workers by a statistical method, the group is called a sample and n = 150.

Sample Unit

A unit selected in the sample is called a sample unit.

Example

Each of the 150 selected workers is a sample unit.

Data

The set of all the observations obtained by inspection of all units of the population or sample is called data.

Example

All the recorded responses about workers' income, age, education level — the complete set of observations from the survey.

Variable Characteristic and Attribute

A variable characteristic can be either numerical or non-numerical. Click a branch to explore.

Variable Characteristic

Varies from unit to unit

Think about it

A college records both types of data about students: quantitative (marks obtained, attendance percentage, fees paid in rupees) and qualitative (stream — Arts/Commerce/Science, medium of instruction — English/Gujarati, hosteller or day scholar). Both types together give the complete picture.

Quantitative vs Qualitative — Quick Comparison

Aspect	Quantitative Data	Qualitative Data
Nature	Numerical — can be measured on a scale	Non-numerical — can be observed but not measured on a scale
Variable Type	Numeric variable	Qualitative variable / Attribute
Examples	Monthly income (₹), age (years), profit of a company, cost of advertising, production (tons), height (meters)	Gender, education level, religion, vegetarian or non-vegetarian
Measurement	Measured in units (rupees, years, tons, meters)	Categorized by labels or descriptions — no unit of measurement
What is collected	Observations on a numeric variable	Observations on an attribute

Real-Life Connection

When Zomato surveys customers, they collect both types: quantitative data (delivery time in minutes, rating out of 5, order amount in rupees) and qualitative data (food preference veg/non-veg, feedback text, area locality). Both are needed to make business decisions.

Key Takeaways

A population is the entire group of units under study; a sample is a selected subset of that population.
Sample size (n) is the number of units in the sample; if n = 150, that means 150 units were selected.
Data is the complete set of observations obtained by inspecting all units of a population or sample.
A variable characteristic varies from unit to unit — it can be numerical or non-numerical.
Qualitative data comes from attributes (non-numeric) — they are observed, not measured on a scale (e.g., gender, education level).
Quantitative data comes from numeric variables — they are measured on a scale with units (e.g., income in rupees, age in years).