Read the labels and scale
This chart shows fictional units produced by four groups, A–D. Read the group labels along the bottom and the units on the vertical scale. The scale starts at zero and rises by 10 each step.
B’s bar reaches 35 units, between 30 and 40. The exact value is also printed above the bar. Find the group named in the question before doing any calculation.
Find a mean from four values
To find the mean for all four groups, read all four values: A has 20, B has 35, C has 15 and D has 30 units.
Add them: 20 + 35 + 15 + 30 = 100. Then divide by the four groups: 100 ÷ 4 = 25. The mean is 25 units; 100 is the total.
Read a new chart
Use this new chart to find the mean number of units for groups A–D.
Read all four values, add them, and divide by the number of groups. Keep the units in your answer.
Try it
What is the mean number of units for groups A–D in this new chart?
- 20 units
- 80 units
Show the answer
20 units
Correct. The total is 12 + 24 + 18 + 26 = 80 units. Divide by four groups: 80 ÷ 4 = 20 units.
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