Major Issues of Statistical Calculations - Research Paper Example

This simplified study considers the impact of psychotherapy on bulimic adolescent girls using the standard scoring system of the Bulimic Investigatory Test, Edinburgh (BITE)(Henderson & Freeman, 1987, p. 18-24). Group 1 scores represent the final tests from the control group, which received no therapy. Group 2 scores are the final test results for the experimental group. The raw data is shown in the table below, with scores being on a scale of 0 (no bulimic behaviour) to 30 (severe bulimic behaviour). Before the experiment, both groups demonstrated similar scores on the baseline test with a mean of ~23.00.

The control group shows a post-experimental phase mean score of 23.27 with a variance of a little over 12. The experimental group demonstrated a mean score of 16.53 and a variance of almost 17. In terms of the data, the experimental group shows significant improvement in the reduction of bulimic behaviour with a seven-point reduction in the mean group score over the baseline. The distribution is higher within the experimental group, likely because of the variable efficacy of psychotherapy on individuals. A review of the raw data shows that only four individuals in the group had scores approaching the group’s baseline, while others showed dramatic improvement. This effect would not be expected in the control group and would contribute to a wider distribution around the mean group score.