Discrete & Continuous Data (Cambridge International IGCSE Mathematics)

Discrete & continuous data

What is discrete and continuous data?

• Numerical data (quantitative data) can be either continuous or discrete

• Continuous data can take any numerical value on a scale

  • e.g. height, length, weight, mass
  • For continuous data the measurements can become more and more accurate the more you 'zoom in'

• Discrete data can only take particular numerical values on a scale

  • Often these are integers

    • e.g. numbers of people or objects

  • But they don't have to be integers

    • e.g. shoe sizes, which include 'half sizes'

Exam Hint Do you need some sort of scale to measure it? If so, it's likely to be continuous data.

Worked Example State whether the data in the following examples is discrete or continuous.

(a) The weights of dogs participating in a dog show.

Answer:

Weight can take any value, so it is continuous

Final answer: Continuous

(b) The lengths of leaves taken from a particular tree.

Answer:

Length can take any value, so it is continuous

Final answer: Continuous

(c) The number of computers owned by each household in a particular city.

Answer:

Only integer (i.e. whole number) values are possible, so it is discrete

Final answer: Discrete

(d) The time taken, to the nearest hour, to complete a task by each person out of a group of people.

Answer:

Although this is time, it wants it 'to the nearest hour', not measured continuously Therefore only certain values are possible, so it is discrete

Final answer: Discrete

(e) The time taken to swim 100 metres by each member of a swimming club.

Answer:

Here there are no constraints placed on the measurement of time, therefore it could take any value, so is continuous

Final answer: Continuous