A health psychologist investigated whether a cognitive bias modification (CBM) training program is effective in reducing public speaking anxiety levels in patients with social anxiety. Participants were randomly allocated to either a CBM group (Na=6N_a = 6Na=6) or a placebo control group (Nb=11N_b = 11Nb=11). Post-intervention anxiety was rated using an ordinal self-report scale. The researcher conducted a Mann-Whitney U test and calculated an observed value of U=13U = 13U=13.
Table 1: Critical values for the Mann-Whitney U test
| NaN_aNa | Nb=6N_b = 6Nb=6 | Nb=7N_b = 7Nb=7 | Nb=8N_b = 8Nb=8 | Nb=9N_b = 9Nb=9 | Nb=10N_b = 10Nb=10 | Nb=11N_b = 11Nb=11 | Nb=12N_b = 12Nb=12 |
|---|---|---|---|---|---|---|---|
| p≤0.05p \le 0.05p≤0.05 (one-tailed) | |||||||
| 6 | 7 | 8 | 10 | 12 | 14 | 16 | 17 |
Using the critical values for the Mann-Whitney U test in Table 1, explain whether the CBM program is effective in reducing anxiety levels.
Practise Edexcel A Level Psychology Research methods and skills with exam-style questions for A Level Psychology. 657 questions covering Research methods and skills, matched to the Edexcel A Level Psychology (9PS0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
