Data can either be discrete or continuous.

• Discrete data consists of integers, units of measurement cannot be split. Only certain values have a meaning.
• Continuous data can be shown on a number line, all points on this line have a meaning. In between two measurements there's always a valid "middle" measurement. So for example, between 156.3cm and 156.4cm there's 156.35cm.

a)

Temperature is a continuous variable, it can take any value between -273.15°C (absolute zero) and positive infinity. For example, 25°C and 26°C have a valid midpoint 25.5°C. Hence, this data is continuous.

b)

The number of Stage 1 students will always be an integer. You cannot split one student into two, for example value 19.5 students does not make sense. Therefore, this is a discrete set of data.

c)

The number of movies downloaded will always be an integer. You can either download a movie successfully or unsuccessfuly, so this is a discrete set of data. It is impossible to split 0 and 1 movies downloaded into 0.5.

d)

Weight is a continuous variable. For example, 54.5kg and 54.6kg have a valid midpoint 54.55kg. Hence, this data is continuous.

e)

When we round continuous variables to the nearest integer, this data becomes discrete, as there are no valid middle measurements between the integers. Therefore, the height of Olympic medalists to the nearest cm is discrete and not continuous.

f)

The number of chocolate bars sold on Monday will always be an integer. There is no middle measurement between 1 and 2 bars sold. You cannot buy half of a bar of chocolate. Therefore, this is a discrete set of data.