Inferential Statistics Flashcards
What is inferential testing?
Statistical procedures that make predictions about populations from mathematical analysis of data taken from samples
In order to decide which statistical test to use what three things need to be decided?
Whether a difference or a relationship between two sets of data is being tested for
What level of measurement the data is
What experimental design has been used
What does the decision about which statistical test relate to?
The aim - if the researcher is looking for a difference or correlation - this should be obvious from the wording of the hypothesis (in this content ‘correlation’ can include correlational analyses as well as investigations that are looking for an association
What are the levels of data/measurement?
Nominal, ordinal and interval/ratio data - they are ranked in relation to one another, getting gradually more informative
What is nominal data?
Data is represented in the form of categories (hence nominal data is sometimes referred to categorical data) e.g. you count the number of male and female students in a class, nominal data is discrete in that 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. It is more informative than nominal data but isn’t fully informative because there is no equal intervals between the data and is often called ‘unsafe data’ as it is often based on subjective opinion rather than objective measures e.g. if asked to rate how happy you are on a scale of 1-10, two people may give the same score but understand it differently
What is interval data?
Data that is based on numerical scales that includes units of equal, precisely defines size e.g. one second in time is the same length as any other second in time
When deciding what statistical test to use what two groups do psychologists put the three experimental designs into?
Related designs - repeated measures and matched pairs
Unrelated designs - Independent measures
What is the way to Remember all the statistical tests?
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