Learn how to summarize data with a single representative value, and visualize it using dot plots and bar graphs.
A representative value summarizes an entire data set with one typical number. The most common one is the average (mean), found by adding all values and dividing by how many there are.
A player scores 6, 2, 9, 5, 4, 6, 3, 5 in 8 attempts. Find the average.
(6+2+9+5+4+6+3+5) ÷ 8 = 40 ÷ 8 = 5
Five students score 70, 85, 90, 75, 80 on a test. Find the average score.
(70+85+90+75+80) ÷ 5 = 400 ÷ 5 = 80
A dot plot shows individual data points stacked above a number line, making it easy to see how values are spread out. A bar graph compares categories using bars of different heights.
A dot plot shows 3 dots above the value 5. What does this tell you?
The value 5 occurred 3 times in the data set
A bar graph compares runs scored: Team A 150, Team B 180. Which team scored more?
Team B, since its bar is taller
1. A cricketer scores 45, 60, 30, 55, 50 in 5 matches. Find the average score.
2. Six days of temperatures are 30, 32, 28, 31, 29, 30. Find the average temperature.
3. A dot plot shows 4 dots above the value 7 and 2 dots above the value 9. What is the total number of data points?
4. A bar graph compares heights of 3 buildings: 40m, 55m, 35m. Which is the tallest?
5. Comparing two classes' average test scores of 72 and 68, which class performed better on average?