Topic 7 of 8 · Grade 7
Data handling: graphs and averages
Tally marks and frequency tables.
Notes for this topic 1 file, in order
Create a free account to download PDFs.
Collecting data
Tally marks and frequency tables.
Graphs
Pictograms, bar graphs, line graphs and simple pie charts. Always give a title, label the axes and use an even scale.
Averages
- Mean: add all the values and divide by how many there are.
- Mode: the value that appears most often.
- Median: the middle value when the values are in order.
- Range: the largest value minus the smallest value.
Worked example: Marks: 6, 8, 5, 8, 9, 7, 6, 8. Find the mean, mode, median and range.
Total = 57; mean = 57 ÷ 8 = 7.125
Mode = 8; in order: 5, 6, 6, 7, 8, 8, 8, 9 → median = (7 + 8) ÷ 2 = 7.5; range = 9 − 5 = 4
Reading graphs
Find the highest and lowest values, totals and differences.
Probability (introduction)
Words like impossible, unlikely, even chance, likely and certain. The chance of getting a head when tossing a coin is ½.
Exam tip: Put numbers in order before finding the median.
Check yourself
- Find the mean of 4, 6, 8 and 10.
- What is the mode of 3, 5, 5, 7, 9?
- What is the chance of rolling a 6 on a fair die?
Show answers
- 7
- 5
- 1/6
Questions about this topic (0)
No questions about this topic yet.
Sign in or create a free account to join in.