A health psychologist investigated whether a new mobile mindfulness app is effective in reducing nicotine craving intensity in smokers trying to quit. Participants were randomly allocated to either a Mindfulness App group (Na=5N_a = 5Na=5) or a Waiting List Control group (Nb=10N_b = 10Nb=10). Craving intensity was rated daily using an ordinal scale. The researcher conducted a Mann-Whitney U test and calculated an observed value of U=9U = 9U=9.
Table 1: Critical values for the Mann-Whitney U test
| NaN_aNa | Nb=5N_b = 5Nb=5 | 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) | ||||||||
| 5 | 4 | 5 | 6 | 8 | 9 | 11 | 12 | 13 |
Using the critical values for the Mann-Whitney U test in Table 1, explain whether the mindfulness app is effective in reducing craving intensity scores.
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.
