Organising data & statistical charts · Ages 12–13
Frequency tables
The frequencies add up to the number of data.
How to do it
Method
The frequencies add up to the number of data
0 × 3 + 1 × 5 + 2 × 4 = 13 books
Another way
Count each value
Count the 2s: 4 of them
In full
To put data in a frequency table: list every possible value, go through the data one by one with a tally mark on the value's row, in fives (four upright and one across), then count each row's frequency. A frequency is how many times its value comes up, and all the frequencies add up to the number of data, which checks that none was missed. Reading the table: 'at least 2' adds the rows for 2, 3, 4…; 'the most people' is the row with the greatest frequency. For the total of the data (how many books in all), multiply each value by its frequency and add: 0 × 3 + 1 × 5 + 2 × 4 = 13. You can count each value straight off without tallying, but tallying misses fewer.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
The table shows how many books each member of a book club read in a week (the left column is the number of books, the right the number of members). How many members are in the club?
Show the answer and working
Answer: 42
The frequencies add up to the number of members: 8 + 10 + 7 + 11 + 6 = 42.
Example 2
The table shows how many books each member of a book club read in a week (the left column is books, the right members). How many read at least 2 books?
Show the answer and working
Answer: 19
'At least 2' means 2, 3 or 4: 8 + 10 + 1 = 19. The 11 who read none and the 4 who read 1 are left out.
Example 3
The table shows a team's goals in each match (the left column is the number of goals, the right the number of matches). Which number of goals comes up most often?
- A. 0
- B. 1
- C. 3
- D. 2
Choose the right answer
Show the answer and working
Answer: B. 1
Look for the greatest frequency: 1 goals, in 11 matches, the most.
Practice questions to try
Try these 5; the answers are at the end. For a whole worksheet, see VIP worksheets below.
1.The table shows how many books each member of a book club read in a week (the left column is the number of books, the right the number of members). How many members are in the club?
Answer:
2.The table shows how many books each member of a book club read in a week (the left column is books, the right members). How many read at least 2 books?
Answer:
3.The table shows a team's goals in each match (the left column is the number of goals, the right the number of matches). Which number of goals comes up most often?
- A. 0
- B. 1
- C. 3
- D. 2
Choose the right answer
Answer:
4.The table shows how many books each member of a book club read in a week (the left column is books, the right members). More than half the club read at least 3 books.
True or false?
Answer:
5.Ka-yee asks 25 families how many televisions they have (the left column is televisions, the right families). What percentage of the families have at least 2?
Answer:
All the answers
- 1. 40
- 2. 26
- 3. C. 3
- 4. False
- 5. 64%
VIP practice notes and papers
Aimed at tests and exams: questions on this topic, new every time, to print or save as a PDF.
- Practice notes: The key point, worked examples step by step, then questions of the same kind to follow, hints fading
- Practice paper: Set out in parts like a school paper, marked, with answers and full working
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