Data collection, recording, and presentation assist us in organise and conclude from our experiences.
We need to know what we are going to do with the data before we start collecting it.
The information gathered should be organised in a table that is easy to grasp and analyse.
The average of a set of numbers can be calculated by finding the sum of the numbers divided by the total numbers of values (n) in the set.
The mean, median and mode of a data set are collectively known as
measures of central tendency.
One of the representative values of data is the arithmetic mean.
sum of all observations
Mean = number of all observations
Another type of central tendency or representative value is mode. The most
common observation in a group of observations is called the mode. If each
value in a data set occurs only once, then all of the values are in mode.
We sometimes refer to this data as having no mode because none of them occurs frequently.
A bar graph is a visual representation of numbers made up of uniformly
sized bars. Double bar graphs make it easy to compare two sets of data at once.
Double bar graphs make it easy to compare two sets of data at once. In our
lives, there are events that are certain to occur, some that are impossible to
occur, and still others that may or may not occur.
The situation, which may or may not occur, has a possibility to occur.

Mean = Sum of the observations by
Number of observations
Mode: The observation which occurs most frequently in a set of data is called Mode.
Median : Median refers to the value which lies in the middle of the data (when arranged
in increasing or decreasing order).
Probability: The measure of the chance of something happening is called probability.
The probability of happening an event may lie between 0 and 1.
When an outcome is certain to happen, its probability is 1.
When an outcome is not possible, its probability is 0.

QUESTIONS
1. Find mean of the first seven whole numbers.
2. Find mean of the first six natural numbers.
3. Calculate the mean of 2, 4, 6, 8, 10, 12, 14, 16.
Calculate the mean of first five multiples of 10.
4.The average marks scored by a student in five subjects is 72. Find his total marks.
5.The marks scored by a student in five subjects are 80, 75, 66, 54 and 91. How much
should he score in the 6th subject to make his average score 75?
6.Find mean of the first five even numbers.
7.Find mean of the first six odd numbers.
8.Calculate the mean: 7.6, 4.8, 8.5, 6.4, 5.6, 3.5, 7.2, 4.4
9.The age in years of 8 teachers of a school are 41, 28, 54, 35, 26, 33, 40, 39, find the mean.
10.What is the range of the following data: 46, 63, 25, 23, 39, 42, 21, 47, 68?

Data Handling Document for Mathematics Class 7

What is Data Handling?
Data handling is a process of collecting, organizing, and analyzing data to extract useful information. It involves various methods such as tally marks, tables, bar graphs, and pie charts to represent data visually.

Importance of Data Handling in Mathematics
- Data handling helps in making sense of large amounts of information
- It allows us to interpret data accurately and draw meaningful conclusions
- It is essential for solving real-life problems using mathematical concepts

Methods of Data Representation
- Tally marks: Used to count and represent data in groups of five
- Tables: Organize data in rows and columns for easy comparison
- Bar graphs: Display data using bars of different lengths to show comparisons
- Pie charts: Represent data in a circular graph to show proportions

Steps in Data Handling
1. Collecting data: Gather information from various sources
2. Organizing data: Arrange data in a systematic manner
3. Representing data: Use appropriate methods to display data visually
4. Analyzing data: Draw conclusions and make predictions based on the data

Conclusion
Data handling is a crucial aspect of mathematics that helps students develop analytical and problem-solving skills. By mastering data handling techniques, students can apply mathematical concepts to real-world scenarios effectively.