2.1 The statistical process

Outside a classroom setting, statistics are rarely calculated in isolation. Data is collected, analysed and interpreted with a purpose, to investigate something or to answer a research question. There is a context in which the statistical investigation sits.

Learners can be introduced to the concept of a statistical investigation using the PCAI cycle (See 2.2). PCAI stands for: pose (a question), collect andanalyse (the data) and interpret (the results).

In Activity 3 you arranged six steps to investigate the idea of putting a play park into a village:

1. Plan the questions to be asked and the type of data to be collected, e.g. age and number of children in a household, opinions.
2. Plan who you are going to ask – everyone in the village or just some residents, and how you are going to contact them.
3. Plan how you are going to organise the data you collect, e.g. table of age categories, number of children, written answers.
4. Collect the data by surveying members of the local community.
5. Process the data by performing calculations such as average number of children per household and producing graphs to visually communicate the data collected.
6. Use the data to answer the initial questions, i.e. decide what the information tells you in the context of potential for opening the play park.

The first three of these (beginning ‘plan’) form the first part of the cycle, pose.

It would be nice if somehow the first three could be highlighted and the word ‘pose’ be added to the side to group these together. Perhaps the sections above could be clickable and these sentences below appear as callouts on the relevant sections?

Then comes the data which needs to be collected and organised; this is the collect stage.

Highlight 4.

Only when this is done can you start to process and represent the data by performing statistical calculations and/or producing graphical displays, the analyse stage.

Highlight 5.

The ‘final’ stage is then to interpret the results by drawing some form of conclusion to answer the initial question that was posed. The word final here is in quotation marks because it is quite likely this will not actually be the final stage of the investigation.

Highlight 6.

Often, when you carry out a statistical investigation, you will end up with more questions than those with which you started. Sometimes there is a need to further develop your understanding of the situation by investigating part of the project in more depth. Hence, the ‘cycle’ part of the process.

Having worked through the investigative process, you may then choose to refine or expand your work by going back around the cycle and asking further questions to be addressed.