AQA All About Maths
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Topic: Statistical Measures (Foundation - Unit 1)
Specification References: S3.3
S3.3
Calculate median, mean, range, mode and modal class.
Candidates should be able to:
use lists, tables or diagrams to find values for the above measures
find the mean for a discrete frequency distribution
find the median for a discrete frequency distribution or stem-and-leaf diagram
find the mode or modal class for frequency distributions
calculate an estimate of the mean for a grouped frequency distribution, knowing why it is an estimate
find the interval containing the median for a grouped frequency distribution
choose an appropriate measure according to the nature of the data to be the ‘average’
Examples
Bags of crisps are labelled as containing 25g.
20 bags are sampled and their weights measured to the nearest gram.
26
25
26
27
24
26
25
26
25
22
26
26
25
24
27
26
25
25
25
25
Work out the mode.
Work out the median.
Work out the mean.
Comment on the label of 25g based on the data and your results from (a), (b) and (c).
view more examples
(from a stem-and-leaf diagram)
Use your diagram to find the median number of people on a bus.
The table shows the height of 100 five-year-old boys.
Height,
h
(cm)
Frequency
8
31
58
3
Calculate an estimate of the mean height of these boys.
Give a reason why your answer to part (a) is an estimate.