Mathematics Notes for Class 9 Statistics

Statistics

In this chapter, you will learn about statistics, how to collect and organize data, and how to represent data using tables and graphs. By the end of this chapter, you will be able to interpret data and solve problems using statistical methods.

Key Concepts

Statistics: The study of collecting, organizing, and interpreting data.
Data: Information collected about people, things, or events.
Frequency: The number of times an item appears in a set of data.

Collecting Data

Data can be collected by asking questions, observing, or measuring. For example, you can collect data about the number of students in each class or the favorite fruit of your friends.

Organizing Data

Once data is collected, it is organized in tables or lists to make it easy to understand.

Use tally marks to count items.
Make a frequency table to show how often each item appears.

Representing Data

Data can be shown using pictures, tables, or graphs. Common ways to represent data are:

Bar Graph: Uses bars to show the frequency of items.
Pictograph: Uses pictures or symbols to show data.
Pie Chart: Shows data as parts of a circle.

Interpreting Data

After organizing and representing data, you can answer questions and make decisions based on the information.

Which item appears most often?
Which item appears least often?
How many items are there in total?

Practice Questions

Collect data about the number of books each student in your class has. Make a frequency table.
Draw a bar graph to show the favorite sports of your friends.
What is the difference between a bar graph and a pictograph?
If 5 students like apples, 8 like bananas, and 3 like oranges, which fruit is most popular?
How can statistics help us in daily life?

Challenge Yourself

Collect data about the weather for a week and represent it using a pictograph.
Make a pie chart showing how you spend your time in a day (study, play, sleep, etc.).

Did You Know?

Statistics is used in sports, business, health, and many other fields.
The word "statistics" comes from the Latin word "status," meaning state or condition.

Glossary

Data: Information collected for study.
Frequency: How often something happens.
Graph: A drawing that shows data visually.
Pictograph: A graph that uses pictures to show data.

Answers to Practice Questions

(Student should make a table with number of books and frequency.)
(Student should draw a bar graph with sports and number of friends.)
A bar graph uses bars; a pictograph uses pictures or symbols.
Bananas are most popular (8 students).
Statistics helps us make decisions and understand information.

Practice collecting and representing data to become a statistics expert!

Mathematics Class 9 - Statistics Notes