Inferential Statistics Flashcards
What is inferential testing?
Statistical procedures that make predictions about populations from mathematical analysis of data taken from samples.
What needs to be decided to decide which statistical test to use?
- Whether a difference or a relationship between two sets of data is being tested for.
- What level of measurement that data is
- What experimental design has been used.
What is nominal data?
Data is represented in the form of categories - hence nominal data is sometimes referred to as categories data. For example, you could count the number of male and female students in a class. Nominal data is discrete in tat one item can only appear in one of the categories.
What is ordinal data?
Involves ranking data in place order with rating scales often being used to achieve this. Ordinal data is more informative than nominal data but it isn’t fully informative because there is no equal intervals between the data and is often called ‘unsafe data’ because it is often based on subjective opinion rather than objective measures. For example, if asked to rate how happy a person is on a scale of 1-10, two people may give the same score but understand that differently.
What is interval data?
Data that is based on numerical scales that includes units of equal, precisely defined size. For example, one second in time is the same length as any other second in time.
How to decide between difference and correlation?
The first thing to consider when deciding which statistical test to use relates to the aim of the investigation - is the researcher looking for a test of difference or correlation. This should be obvious from the wording of the hypothesis. In this context, ‘correlation’ can include correlation analyses as well as investigations that are looking for association.
How to decide between experimental designs?
When deciding the statistical test that would need to be used, psychologists group the three different experimental designs into two groups.
Related design = repeated measures and matched pairs.
Unrelated designs = independent measures
What is the acronym to remember the statistical test table?
Carrots Should Come Mashed With Swede Under Roast Potatoes.
