# Lecture 2 - Analysis of Variance (ANOVA) Flashcards

What is variability?

It is to do with the range/spread of data. Data can have the same mean but different variabilities, or the same variability but different averages

What do parametric tests assume?

They assume a normal population distribution

What is the normal distribution?

a mathematical function that defines the distribution of scores in a population. It does this with regard to two ‘population parameters’ - Mu/µ and Sigma/σ

Most (but not all) data is normally distributed

What does Mu/µ represent?

the population mean

is involved in calculating the normal distribution

What does Sigma/σ represent?

the population standard deviation (variance)

is involved in calculating the normal distribution

What does this show in terms of a normal distribution?

The same µ (pop mean) but different σ (std. dev./variance)

What does this show in terms of a normal distribution?

The same σ (pop std. dev /variance) but different µ (pop mean)

What does this show in terms of a normal distribution?

A different σ (pop std dev) and the same µ (pop mean)

What do variances look like when:

H0 is true

H1 is true

H0 is true - scores almost completely overlap

H1 is true - very little overlap between score distribution

What are the two kinds of experimental error?

individual differences error

measurement error

these are the two main kinds, there are others but these are the main ones. In a real experiment, both would contribute to each subjects’ score

Why do we look at experimental error?

It contributes to the differences found between treatment conditions

So we must try to find out how much of the difference can be attributed to experimental error

What can tell us about experiemental error?

The variability of subjects in the same condition ought to tell us about experimental error

What are treatment effects?

the systematic source of variability that comes from the different conditions of the IV used in each treatment grouo

What does partitinoning the deviations mean?

Basically, finding out the standard deviations

What does A1, A2, A3 etc mean?

the different treatment conditions