Data Handling
Tally Charts & Frequency Tables
Tally marks record counts in groups of five — four lines with a fifth crossing them. The frequency is how many times something happens. A frequency table lists each item next to its count.
Example 1: How many does one full tally group stand for?
A full group (four lines crossed by a fifth) stands for 5.
Example 2: A frequency table shows what for each item?
The number of times it occurs (its frequency).
Quick recap
- Tally marks group counts in fives.
- Frequency = how many times something happens.
✓ Quick check
Two full tally groups stand for ___ ?
5 + 5 = 10.
A frequency table shows the ___ of each item.
It shows the count (frequency) of each item.
Bar Graphs with a Scale
A bar graph shows data using bars whose heights give the values. The scale tells how much each unit stands for. If the scale is 5, a bar that reaches 4 units means 4 × 5 = 20.
The tallest bar shows the most and the shortest shows the least.
Example 1: On a graph with scale 10, a bar reaches 3 units. What value is that?
3 × 10 = 30.
Example 2: What does the tallest bar show?
The most (the highest value).
Quick recap
- The scale tells how much each unit stands for.
- Tallest bar = most; shortest bar = least.
✓ Quick check
With a scale of 5, a bar that reaches 6 units stands for ___ ?
6 × 5 = 30.
On a bar graph, the shortest bar shows the ___ ?
The shortest bar shows the least.
Pie Charts & Mode
A pie chart shows parts of a whole as slices of a circle. A slice that is half the circle means half the data chose that option.
The mode is the value that appears most often. In the data 3, 5, 3, 7, 3 the mode is 3 because it appears the most.
Example 1: Find the mode of 3, 5, 3, 7, 3.
3 appears most often, so the mode is 3.
Example 2: A pie chart shows half the circle for football. What does that mean?
Half of the people chose football.
Quick recap
- A pie chart shows parts of a whole as slices.
- Mode = the value that appears most often.
✓ Quick check
What is the mode of 2, 4, 4, 6, 4, 8?
4 appears three times, more than any other, so the mode is 4.
If a pie chart shows half the circle for cricket, that means ___ ?
Half the circle means half the people chose cricket.
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