Page 2 - Lesson note- 2- Ch 14 Statistics (Frequency Distribution)

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What Is Grouped and Ungrouped Data?

Ungrouped data is raw data that has not been placed in any category

For example, you know that 350 people are living in your area. This is raw data and is
not grouped, i.e. divided into any category.

The moment this raw data is categorized, it becomes grouped data. For example, there
are 50 children and 300 adults. This data is now organized as you have clear
information about the number of children and adults present in your locality.

Discrete and Grouped Data

Data may be discrete or continuous.
Discrete data can only take particular values (usually whole numbers) such as the
number of children per family.
Continuous data can take any value in a given range, for example mass, height, age
and temperature.

Sometimes, the collected data can be too numerous to be meaningful. We need to
organize data in some logical manner in order to make sense out of them. We could
group data into classes. Each class is known as a class interval.

Example:

The data below shows the mass of 40 students in a class. The measurement is to the
nearest kg.

55 70 57 73 55 59 64 72
60 48 58 54 69 51 63 78
75 64 65 57 71 78 76 62
49 66 62 76 61 63 63 76
52 76 71 61 53 56 67 71

Construct a frequency table for the data using an appropriate scale.