Class 8 Math Data Handling Notes
Data Handling – Class 8
Hi kids! This chapter is all about Data Handling. We’ll learn how to organize information and understand the chances of things happening (probability)!
Organizing Data
Data is just a collection of information. To make sense of it, we need to organize it. Here are some ways:
1. Frequency Distribution Table:
This table shows how often each item or value appears in the data.
Example: Scores of 20 students in a math test (out of 10):
| Score | Frequency |
|---|---|
| 5 | 2 |
| 6 | 5 |
| 7 | 7 |
| 8 | 4 |
| 9 | 2 |
This table tells us that 2 students scored 5, 5 students scored 6, and so on.
Graphical Representation of Data
Graphs make it easier to visualize and understand data.
1. Bar Graph:
Uses bars of different lengths to represent the frequency of data.
Example: A bar graph can show the number of students in each grade of a school.
2. Histogram:
Similar to a bar graph, but used for continuous data (data that can take any value within a range). The bars touch each other.
Example: A histogram can show the distribution of heights of students in a class.
3. Pie Chart:
A circle divided into sections, where each section represents a proportion of the whole data.
Example: A pie chart can show the percentage of different types of books in a library.
4. Line Graph:
Uses lines to connect data points, showing trends over time.
Example: A line graph can show the change in temperature over a day.
Probability
Probability is the chance that something will happen. We measure it from 0 (impossible) to 1 (certain). It can also be expressed as a percentage.
Formula for Probability:
Probability = (Number of favorable outcomes) / (Total number of possible outcomes)
Example: What is the probability of rolling a 3 on a standard six-sided die?
Solution: There is 1 favorable outcome (rolling a 3) and 6 possible outcomes (rolling 1, 2, 3, 4, 5, or 6). So, the probability is 1/6.
Applications of Data Handling and Probability
1. Sports:
Analyzing player statistics, predicting match outcomes.
2. Weather Forecasting:
Predicting the chance of rain, snow, or sunshine.
3. Business:
Analyzing sales data, predicting future trends.
4. Games of Chance:
Understanding the odds of winning a lottery or a card game.
Data handling and probability are important tools for understanding and making decisions about the world around us.
Data Handling Quiz – Application Problems
1. Weather Data: The table below shows the number of sunny days in a city for each month of the year. Which month had the most sunny days?
| Month | Sunny Days |
|---|---|
| Jan | 15 |
| Feb | 20 |
| Mar | 25 |
| Apr | 22 |
| May | 28 |
2. Student Scores: A bar graph shows the scores of students in a class on a science test. If the bar for a score of 80 is twice as tall as the bar for a score of 70, how many times more students scored 80 than 70?
3. Favorite Sports: A pie chart shows the distribution of favorite sports among students. If the section for “Football” represents 50% of the circle, what fraction of the students prefer football?
4. Plant Growth: A line graph shows the growth of a plant over several weeks. If the line is steadily going upwards, what does this indicate about the plant’s growth?
5. Coin Toss: What is the probability of getting a “head” when you toss a fair coin?
6. Rolling a Die: What is the probability of rolling an even number on a standard six-sided die?
7. Drawing a Card: A bag contains 5 red balls and 3 blue balls. What is the probability of drawing a blue ball at random?
8. Survey Data: A survey asked students about their favorite subjects. The results are shown below. If 100 students were surveyed in total, how many students chose Math as their favorite subject?
| Subject | Percentage |
|---|---|
| Math | 30% |
| Science | 25% |
| English | 20% |
| History | 25% |
9. Game of Chance: A spinner has 8 equal sections, numbered 1 to 8. What is the probability of spinning a number greater than 5?
10. Product Sales: A company tracks the sales of a product over a year using a line graph. If the line graph shows a peak in sales in December, what does this likely indicate?
