Data Handling
Double Bar Graphs & Pie Charts
A double bar graph shows two sets of data side by side, so we can compare them — for example, the marks of boys and girls in each subject. The taller bar shows the larger value.
A pie chart shows parts of a whole as slices of a circle; a slice that is half the circle stands for half the data.
- A double bar graph compares two sets of data.
- A pie chart shows parts of a whole as slices.
Mean, Median & Mode
The mean (average) is the sum of the values divided by how many there are. The median is the middle value when the data is arranged in order. The mode is the value that appears most often.
For 2, 4, 6: mean = (2 + 4 + 6) ÷ 3 = 4. For 3, 5, 7: the median is 5.
- Mean = sum ÷ number of values.
- Median = middle value (in order); mode = most frequent value.
Probability
Probability describes how likely something is. An event can be certain (sure to happen), impossible (cannot happen), equally likely (a 50-50 chance), or less likely (unlikely).
Getting heads or tails on a fair coin is equally likely. The sun rising tomorrow is certain. Rolling a 7 on a normal six-sided dice is impossible.
- Probability words: certain, impossible, equally likely, less likely.
- A fair coin gives heads or tails as equally likely.