Lecture 1

SPSS Survival Manual by Julie Pallant - textbook for SPSS https://doi.org/10.4324/9781003117452

Measuring Human Behaviour

How would you measure:

• Stress? - self report, heart rate

• Creativity? - responses to tricky questions

• Sleep quality? - sleeping time, EEG

• Attention span? - how long can you hold focus on a moving object

Some measures may be subjective rather than objective, such as measuring creativity.

Variability

Normal distribution forms a bell shaped curve with the majority in the middle around the average, and less around the edges - extremes

Causality

1. Co-variance: two aspects are actually rated to each other

2. Temporal precedence: a change in the IV happening before the change in DV

3. Elimination of confounds: no other variables are affecting the results

Questions to ask when looking at an association

Does this grouping make sense?

Is this difference meaningful?

What else might affect the DV?

Grouping Methods:

• Group by existing variables (independent variables) - Quasi-Experimental Approach

• Group by manipulated variables - Experimental Approach

Experimental approaches allow to conclude causality, by contrast to correlational research.

Correlational research can not answer the following questions:

1. Does changing x cause changes in y?

2. Does changing your cause changes in x?

3. Are they both affected by z?

p-value: probability that the null hypothesis is true

Null Hypothesis: the claim that the effect being studied does not exist

Type 1 Error: claimed effect was there when it was not

Type 2 Error: missed an effect that was present

Analysis of Variance (ANOVA) provides more precise conclusions compared to t-test