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Statistical Analysis:

STATISTICS - DATA TYPES

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Statistical Analysis:

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ram vnet
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Dec 20, 2025
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3 min read

Understanding Data Types.

Statistical analysis is the process of collecting, organizing, Analysing, and interpreting data to discover patterns and make decisions.

Before applying any statistical method, the most important step is understanding what type of data you are working with, because different data types require different analysis techniques.

Why Data Types Matter in Statistics?

Using the wrong statistical method on the wrong data type can lead to:

Incorrect conclusions

Misleading results

Poor decision-making

For example, you cannot calculate an average for categories like colours or names, but you can calculate an average for height or marks.

That’s why data types are the foundation of statistical analysis.

Main Types of Data in Statistics

Statistical data is broadly divided into two main categories:

Qualitative (Categorical) Data

Quantitative (Numerical) Data

Let’s break these down clearly.

  1. Qualitative (Categorical) Data :

Qualitative data describes qualities or characteristics.

It does not involve numerical values that can be measured mathematically.

Key Features:

Descriptive in nature

Represents categories or labels

Cannot be averaged

Examples:

Gender (Male, Female, Other)

Blood group (A, B, AB, O)

Eye colour

Type of device (Mobile, Laptop, Tablet)

Types of Qualitative Data:

a) Nominal Data

Categories without any order

No ranking

Examples:

Nationality

Colours

Types of food

You cannot say one category is greater or smaller than another.

b) Ordinal Data :

Categories with a meaningful order

Differences between values are not measurable

Examples:

Education level (High school, Bachelor’s, Master’s)

Customer satisfaction (Low, Medium, High)

Movie ratings (Poor, Average, Good, Excellent)

You know the order, but not the exact difference between levels.

  1. Quantitative (Numerical) Data :

Quantitative data represents numbers that can be measured or counted.

Key Features:

Numerical

Can be used for calculations

Can be averaged

Examples:

Age

Height

Number of students

Exam scores

Types of Quantitative Data:

a) Discrete Data

Countable values

Usually whole numbers

Examples:

Number of children in a family

Number of cars in a parking lot

Number of followers

You cannot have fractions like 2.5 cars.

b) Continuous Data

Measurable values

Can take any value within a range

Examples:

Weight

Temperature

Time

Distance

Continuous data can include decimals (e.g., 65.7 kg).

Levels of Measurement (Advanced but Important)

Statistical data is also classified into four levels of measurement:

Nominal – Labels only (e.g., blood type)

Ordinal – Ordered categories (e.g., rankings)

Interval – Ordered with equal intervals, no true zero (e.g., temperature in °C)

Ratio – Ordered with equal intervals and a true zero (e.g., height, weight)

Each level determines which statistical operations are valid.

Choosing the Right Statistical Method

Data Type Suitable Analysis

Nominal Frequency, Mode

Ordinal Median, Rank analysis

Discrete Mean, Median

Continuous Mean, Standard Deviation

Choosing the correct method ensures accuracy and reliability.

Real-Life Example

If you’re analysing a student survey:

Gender → Qualitative (Nominal)

Satisfaction level → Qualitative (Ordinal)

Marks obtained → Quantitative (Discrete)

Time spent studying → Quantitative (Continuous)

Each variable needs a different analysis approach.

Final Thoughts

Understanding data types is the first and most critical step in statistical analysis.

Once the data type is correctly identified, choosing the right statistical tool becomes much easier and more accurate.

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