Discrete and continuous data
Discrete and continuous data.
- Discrete data have separate possible values, usually from counting.
- Continuous data are measured and can take any value within a range.
- A rounded measurement is still a measurement of a continuous quantity.
Example 1
Classify the number of siblings a student has as discrete or continuous.
It is a count: 0, 1, 2, … . Values such as 1.4 siblings are impossible.
Example 2
Classify the mass of a parcel as discrete or continuous.
Mass is measured and can take any value within a range, even if the scale rounds its reading.
Your turn
A race time is recorded to the nearest second. Is the underlying time discrete or continuous?
Check answer
Rounding the recording does not change the measured quantity. The actual time can fall between whole seconds.
Classify the number of goals in a match.
Check answer
Goals are counted in whole numbers.
A person’s height is recorded as 168 cm. Classify height.
Check answer
Height is measured. A more precise instrument could record values between the stated centimetres.
A game awards only 0, 0.5, 1, 1.5, … points. Classify the score.
Check answer
Only fixed separated values are possible. Discrete data do not have to be whole numbers.
Classify the temperature of a room.
Check answer
Temperature can take any value within a range; the thermometer gives a rounded measurement.
A race time is recorded to the nearest second. Is the underlying time discrete or continuous?
AnswerRounding the recording does not change the measured quantity. The actual time can fall between whole seconds.
Classify the number of goals in a match.
AnswerGoals are counted in whole numbers.
A person’s height is recorded as 168 cm. Classify height.
AnswerHeight is measured. A more precise instrument could record values between the stated centimetres.
A game awards only 0, 0.5, 1, 1.5, … points. Classify the score.
AnswerOnly fixed separated values are possible. Discrete data do not have to be whole numbers.
Classify the temperature of a room.
AnswerTemperature can take any value within a range; the thermometer gives a rounded measurement.