Collecting and recording dataPrint
Continuous data is data which can take any value. Examples include time, height and weight.
Because continuous data can take any value, there are an infinite number of possible outcomes. So continuous data must be grouped before it can be represented in a frequency table or statistical diagram.
When choosing groups for the data, make sure that each piece of data can be placed in one (and only one) of the groups.
You are investigating the length of time each member of a class spends on the internet per week. Look at the class groupings below - do you think they are right?
|0 ≤ time ≤ 10|
|10 ≤ time ≤ 20|
|20 ≤ time ≤ 30|
These groups are wrong, because the times of '10 hours' and '20 hours' can be entered into two different groups.
For example, the time 10 hours can be entered into 0 ≤ time ≤10 (where time is less than or equal to 10 hours), and also into 10 ≤ time ≤ 20 (where time is more than or equal to 10 hours).
|0 < time < 10|
|10 < time < 20|
|20 < time < 30|
These groups are also wrong, because the times '10 hours' and '20 hours' cannot be entered into any of the groups.
For example, the time 10 hours can neither be entered into 0 < time < 10 (where time is less than 10 hours), nor can it be entered into 10 < time < 20 (where time is more than 10 hours).
|0 ≤ time < 10|
|10 ≤ time < 20|
|20 ≤ time < 30|
These groupings are right. '10 hours' is included in the second group, but not the first and '20 hours' is included in the third group, but not the second.