DClinPsy Portfolio Volume 1 of 3 - University of Hertfordshire ...

Due to the small sample size in the groups that reported a history of ED or mental illness
in their family, a non parametric analysis was carried out, results of which can be viewed
in Table 22 below.
Table 22- Test for mean difference between mental illness and eating disorder family
history in relation to inflexibility
Comparison Mean difference (SE) Z p value Effect size
1. Eating Disorder History
(1-tailed) (Cohen’s d)
yes/no - Inflexibility
-6.96 -1.86 0.03 0.57
2. Mental illness History
yes/no - Inflexibility
-1.84 -0.54 0.29 0.15
As can be seen from Table 22 there is a significant mean difference regarding ED history
and inflexibility with a medium effect size. There is no significant difference in
inflexibility in relation to mental illness.
2) Inflexibility in relation to drug and alcohol use
Of the 88 participants that replied to the question on illicit drug use 10 (11%) reported
using alcohol and 78 (89%) reported no drug use. With regards to alcohol use 20 (23%)
reported having used alcohol and 68 (77%) said they had not. Boxplots (Figure 17, 18)
and descriptive statistics (Table 23) can be found in appendix 12. Again, the small
number of adolescents in this sample reporting drug or alcohol use led to a non
parametric analysis being undertaken.
Table 24- Test for mean difference between reported alcohol and drug use in relation to
inflexibility
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