Unit 6: Business Decision Making - Techniques to analyse data
Frequency distributions
The Human Brain
The human brain finds it difficult to make sense of a large quantity of data, however once it is organised and presented, a large amount of information can be derived from it.
Data Classification
Qualitative
Qualitative data is data which is not numerically significant.
- colour of cars
- feelings about a new product
- taste
- thoughts on the ride
Quantitative
Quantitative data is data which is expressed in numerical terms
- number of hours worked
- amount spent
- cups of coffee drunk
- number of cars passing per hour
Data Classification
- Continuous Data
- data that is measured on an interval scale (such as length or weight)
- Discrete Data
- whole values (obtained by counting)
- Ordinal Data
- given a numerical value but only for comparative purposes (giving a score between 1 and 10).
- Categorical Data
- no numerical value (such as choice of newspaper)
How would you define the following?
- heights of checkout operators
- choice of summer fruit
- sales of summer fruit per day
- weekly earnings by employees in Asda
- number of shoppers per day at Tesco
- market research survey into consumer reaction to a new product
Method of Travel
Twenty people were asked how they travelled to work.
Person |
Mode of Travel |
Person |
Mode of Travel |
Person |
Mode of Travel |
Person |
Mode of Travel |
1 |
car |
6 |
car |
11 |
bus |
16 |
car |
2 |
car |
7 |
cycle |
12 |
car |
17 |
car |
3 |
bus |
8 |
bus |
13 |
walk |
18 |
car |
4 |
walk |
9 |
train |
14 |
walk |
19 |
bus |
5 |
cycle |
10 |
walk |
15 |
cycle |
20 |
car |
As a table of data it can be complex to infer information from it. If we create a frequency table then we can find it easier to intrpret information from the data.
Mode of Travel |
Frequency |
Relative Frequency |
Car |
8 |
40% |
Bus |
4 |
20% |
Walk |
4 |
20% |
Cycle |
3 |
15% |
Train |
1 |
5% |
Grouping
- Ungrouped
- all numbers are included to measure the frequency
- Grouped
- intervals are used to measure the frequency
Class Boundary
- class boundaries and intervals
- these should be a convenient number such as 10,20, 25
- for example with a data range of 100 to 298 you could have
100-119, 120-129, 130-139, 140-149
and so on...
Irregular Intervals
A histogram is a variation of a bar chart in which it is the area (not the height) which represents the frequency. With regular class intervals the height is directly proportional to the class frequency, with irregular intervals (e.g. age) it may be appropriate to increase class widths.
Regular Intervals
Spending at Tesco Metro (£) |
Number of Shoppers |
0-9.99 |
123 |
10-19.99 |
45 |
20-29.99 |
99 |
30-39.99 |
56 |
40-49.99 |
47 |
50-59.99 |
38 |
60-69.99 |
17 |
70-79.99 |
0 |
Irregular Intervals
Daily Sales (£) |
No. of Stores |
Up to 1,999 |
10 |
2,000-3,999 |
40 |
4,000-7,999 |
100 |
8,000-11,999 |
120 |
12,000-19,999 |
60 |