Data Handling (NCERT Ch. 3)

• Find the mean (average), median, and mode of a data set.
• Understand and interpret bar graphs and double bar graphs.
• Understand basic probability as a measure of chance.

1. Mean = sum of all observations ÷ number of observations.
2. Median = the middle value when data is arranged in order (average of two middle values if the count is even).
3. Mode = the value that occurs most frequently in the data.
4. A double bar graph compares two sets of data side by side for each category.
5. Probability of an event = (number of favourable outcomes) ÷ (total possible outcomes).

Find the mean of: 4, 8, 6, 10, 2

Sum = 4+8+6+10+2 = 30
Mean = 30 / 5 = 6

• Forgetting to arrange data in order before finding the median.
• Confusing mean (average) with median (middle value).
• Assuming every data set has exactly one mode (some have none, some have multiple).

• Find the median of: 3, 7, 2, 9, 5.
• Find the mode of: 2, 3, 3, 5, 3, 7.

Open the Practice tab for graded questions on Data Handling (NCERT Ch. 3).