Posted: April 29th, 2015

PRP4014/PHP4006 Advanced RM/Stats/week 11 SPSS Midterm Test I

PRP4014/PHP4006 Advanced RM/Stats/week 11 SPSS Midterm Test I

These Tasks will be based on a single data file: midterm1_thurs.sav
You want to examine whether Cannabis use affects reward-based decision-making. You recruit 28 Cannabis users and 28 No Drug Control participants. They all perform a decision-making task in which they are required to learn over 5 consecutive task Blocks to avoid bad choices and make good choices – higher scores are equivalent to better performance. You also collect measures of Behavioural Approach System (BAS; Higher Score = higher sensitivity to rewards) and Behavioural Inhibition System (BIS; Higher scores = higher sensitivity to punishment), both of which are proposed to be related to reward-based behaviour.
Task 1
As a preliminary analysis you use independent-samples t-tests to examine potential differences between the No drug and Cannabis User groups on the BIS (BIS) and BAS (BAS) measures. You can assume normality.
Task 2
Perform a mixed-ANOVA with ‘Group’ as the between-subject variable (2 levels) and ‘Block’ defined as the within-subjects Factor (5 levels). For the within-subjects Factor, you use the 5 Block measures of decision-making performance (Block1to Block5). Make sure you also collect the following additional data:
1. Descriptive data.
2. Perform a ‘Repeated’ contrast on ‘Block’.
3. Ask for Marginal Means Main effects tests for Block (Sidak adjustment).
4. Block*Group interaction profile plot.
5. You can assume normality, but do test homogeneity of variance.
Perform follow-up analyses by using independent-samples t-tests to compare between the two groups over the 5 levels of the within-subjects Factor (Block).
Task 3
You now perform a multiple regression to predict performance after 5 Blocks (Block5) experience of the task from two variables: Behavioural Approach (BAS) and Behavioural Inhibition (BIS). You use a Forced Entry method and examine the relationship in the two groups (use ‘Split file’ option). Ensure you collect the appropriate basic diagnostics and plots to assess the assumptions required of multiple regression.
Make sure you bring this output to your test on Thurssday 30th April 2pm-3pm – you can bring either Electronic or Hard copies (or both). The test is open book (no Google or Social Media!). Try to arrive early, as I’ll allow entry to the Maclab about 15 mins before the start of the test to make sure you are all logged in etc in