Exercises: Types of Data
Question 2.1
What types of variable are the following (nominal, ordinal, metric discrete or metric continuous)?
- Number of teeth
- Age
- Age last birthday (in years)
- Has patient visited their dentist in the last year
- Social class
- Pocket depth
- Hardness of filling material
- Colour of filling material
- Type of radiograph
- Calcium:phosphorus ratio in teeth
- Severity of gum disease
Question 2.2
The following table is en extract from a paper looking at caries prevalence amongst children in Wick, Scotland. What types of variable are represented here?
(dmft = decayed, missing and filled teeth total)
| Variable | |
| n | 106 |
| mean | |
| dmft | 2.63 |
| % caries free | 27.4% |
| Decayed/filled teeth | 2.39 |
| Extracted teeth | 0.75 |
| proportion | |
| Social class I & II | 15.0% |
| Social class III | 42.5% |
| Social class IV & V | 30.2% |
| Social class unknown | 12.3% |
