Home > Subjects > Mathematics > Level 3 - statistics and modelling > 3.5 Statistical investigation (AS90645) > Key tips
- Subject: Mathematics
- AS: AS90645
- Level: 3
- Credits: 3
- Internal
Statistics and modelling 3.5 Select and analyse continuous bi-variate data
Key tips
- You are expected to select your own data sets for this investigation. This may be from existing databases, from Internet sites, or from other sources. Alternatively, you may collect the data yourself.
- Take time to study your data carefully, identify what you are trying to show, and then write your purpose statement clearly
- Take care identifying variables that will enable you to analyse your data and draw conclusions. Don’t forget to name them in your plan. Describe your data collection method or data source.
- A scatter graph or diagram will help you to see visually if there is any relationship between the two sets of data.
- Use several regression models to investigate the relationship between the variables and interpret this. Comment on the ‘fit’ of each model. Find the regression equation and correlation coefficient. Identify any trends, outliers, clusters etc.
- Remember to answer your question/purpose including a description of the relationship and draw conclusions. This may include predictions that can be made from your regression equations or ways of improving your model.
- For Achievement with Merit, you need to understand the difference between correlation and causality and relate it to the context of your investigation.
- It is expected that you will use appropriate technology such as spreadsheet software or a graphics calculator for exploration of data and communication of findings.
- This achievement standard does not assess sampling concepts or the use of confidence intervals (see Mathematics 2.5, AS90288 and Statistics 3.2, AS90642).
- Check out the I Can Do Sheet Level 3 Statistics from www.nzamt.org.nz for a list of essential skills for each achievement standard.
