RxPG - Conception of Variables in Biostatistics

Characteristics which show variability or variation are known as variable. eg. Height, WBC count, sex, religion, vomiting episodes etc.

Classification:
A. Quantitative- A variable for which resulting observations can be numerically measured. 2 types-

a. Continuous: All values possible ( in some range). Eg. Weight of an adult (70.12 kg, 70.121 kg, 70.122 kg………all these weights have theoretical existence, but for convenience of measurement we consider larger units-70.0 kg, 70.5 kg etc)

b. Discrete: There are gaps between the possible values. Eg. We can have WBC count of 5000 or 5001 or 5002/mm3, but we cannot have the WBC count of 5000.5 or 5001.5/mm3 because we cannot count a “half” of a WBC

B. Qualitative: Numerical measurement is not possible, eg. Occupation- doctor, engineer, businessman, farmer.

Examples:

1. Rainfall recorded at the area X- Quantitative ( continuous)
2. price of book in different shops- Quantitative ( discrete)
3. Number of motorbikes manufactured by a company each month- Quantitative ( discrete)
4. the colour of people’s eye-Qualitative
5. The number of rooms with attached bath in a hotel -Quantitative ( discrete)
6. The annual water consumption by a household- Quantitative ( continuous)
7. The constituents found from drilling into the earth-Qualitative
8. The speed of the F1 car- Quantitative ( continuous)

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