Class 7 Data Handling Worksheet – Mean, Median, Mode & Pie Charts

Data-handling worksheet for Class 7, including mean, median, mode, range, and pie charts. Includes solved examples and challenging problems to help your child analyse and interpret data at an advanced level.

What is Data Handling?

At Class 7, Data Handling becomes analytical. We move from simply reading and displaying data to calculating statistical measures and drawing conclusions from them. The focus shifts to understanding what data tells us — not just what it shows. We work with mean, median, mode, and range to summarise data sets, interpret double bar graphs, and calculate angles for pie charts.

Key Concepts

Mean (Average): Found by adding all values and dividing by the number of values. It gives us a single number that represents the entire data set, but it can be pulled up or down by extreme values.

Median: The middle value when data is arranged in ascending order. If there is an even number of values, the median is the average of the two middle values. Unlike the mean, it is not affected by extreme values.

Mode: The value that appears most frequently. A data set can have no mode, one mode, or multiple modes.

Range: The difference between the highest and lowest values. It tells us how spread out the data is.

Pie Charts: A circle divided into sectors where each sector represents a category. The angle for each sector is calculated using the formula: Angle = (Value ÷ Total) × 360°.

Solved Example

Find the mean, median, mode, and range of: 5, 8, 3, 8, 10, 8, 6.

Step-by-Step Solution

First, calculate the mean. Add all values: 5 + 8 + 3 + 8 + 10 + 8 + 6 = 48. Divide by the count: 48 ÷ 7 = 6.86.

Next, find the median. Arrange in ascending order: 3, 5, 6, 8, 8, 8, 10. There are 7 values (odd), so the median is the 4th value, which is 8.

Then, find the mode. The value 8 appears 3 times, more than any other. The mode is 8.

Finally, calculate the range. Highest value minus lowest value: 10 − 3 = 7.

Practice Problems

• The heights of 6 students are given in centimetres. Find the mean and median height, noting that with an even number of values the median requires averaging the two middle numbers. → Mean and Median with Even Data Sets
• The mean of five numbers is given as 18, and four of them are known. Find the missing fifth number by working backwards from the total. → Finding a Missing Value from the Mean
• A class voted on favourite subjects. Calculate the pie chart angle for each subject using the formula, then identify which subject takes up the largest sector. → Calculating Pie Chart Angles
• The median of a data set with one unknown value is given. Find the unknown by placing it in the correct position within the ordered sequence. → Finding an Unknown from the Median
• A cricket team's scores across 5 matches include one unknown. The mean score is given. Find the unknown score, then calculate the median of the complete data set. → Combined Mean and Median Problem
• A shopkeeper's daily sales for 6 days include one unknown value. The median sales figure is given. Find the unknown, then calculate the mean sales for the week. → Real-World Multi-step Problem

Scoring Guide

• 20–24 marks: Excellent! You have mastered data handling. Move on to probability and advanced statistics.
• 15–19 marks: Very Good! Practice more on pie charts and finding unknown values when mean or median is given.
• 10–14 marks: Good Effort! Focus on understanding when to use mean, median, and mode. Practice arranging data in order first.
• 0–9 marks: Keep Trying! Review the formulas carefully. Practice calculating mean, median, and mode with simple data sets daily.

Tips and Common Mistakes

Always arrange data in ascending order before finding the median. Skipping this step is the most common error and leads to a wrong answer every time.

Do not confuse mean and median. The mean requires addition and division. The median requires sorting and finding the middle value. They are different measures and often give different results.

When finding the mean, divide by the total count of values, not by any other number. Forgetting to divide, or dividing by the wrong count, is a frequent calculation mistake.

For pie charts, remember that all angles must add up to 360°. Use this as a check after calculating each sector.

When a problem gives you the mean or median and asks you to find a missing value, work backwards. Calculate the total first using the formula, then subtract the known values.

Read bar graph scales carefully before extracting any values. A misread scale will make every subsequent calculation wrong.