Interpreting Data

10. What are the steps to statistical literacy?

To be statistically literate you do not need to be good at maths. You do not need to be able to use equations - you just need to ask questions.

When making decisions about studies that you read in the paper how do you decide what is best for you?

• Have you given up margarine because, according to a study, it contains more bad fat than butter ever did?
  
  
• Are you convinced by advertisements and so decide that your drink of choice will be tea because it contains antioxidants? Antioxidants are good because they destroy free radicals which are bad because they can cause damage to cell components that leads to cancer.
  
  
• Have you stayed with coffee because it helps keep your gall bladder in good health?

On what do you base these lifestyle decisions? When you read about a study what questions do you ask? From the work that you have done in the three statistical literacy modules you might like to ask a number of questions about the source of the data, the representation of the data and the interpretations that are made using that data.

The Source of the Data

How were the variables that were used to examine the property defined and measured?

How were the data collected and by whom? (Remember, even experts make up data.)

For example, early in 2000 an athlete claimed that 70-80% of Australian athletes vying for a spot on the Australian team were using a growth hormone IGF-1 in an effort to improve their performance. This is immediately reported in the TV news. But where did this data come from? It is really a guess and an example of what Dan Seligman (1961) calls "phony statistics". This data was at best anecdotal and at worst made up!

The Data

The data can be:

• numbers (frequencies and relative frequencies)
• tables
• bar charts/ histograms/ pie charts
• line graphs
• scatter plots

What do the data say?

How were the data presented?

Was the method of presentation appropriate for the variables being measured?

Interpreting the Data

Do the data justify the interpretation/argument that has been presented?

Can the results from the study of the sample be inferred for the population?

Do the results justify claims for association, correlation or causation?

Being statistically literate means being aware of all these issues. Asking the right questions will help you to critically analyse reports of studies which you may read or hear about in the media or elsewhere.

Well Done! You have reached the end of Module 3.

Next - Menu