ABSTRACT
Slimming clinics aim to help people lose weight by offering encouragement and support about dieting through regular meetings. A study was carried out to assess their effectiveness. Half of the clients participating in the study were randomly selected to receive a technical manual containing slimming advice based on psychological behaviorist theory to investigate if this would help them to control their diet. Some of the clients had previously tried to slim whereas others were novices. The data collected are shown in Table 5.1. (They are also given in Hand et al., 1994.) The response variable resp was defined as follows:
weight after three months of treatment− ideal weight initial weight− ideal weight (5.1)
The design can be thought of as a 2×2 factorial design where manual (1: received a manual, 2: did not) is crossed with exper (1: previous slimming experience, 2: novice). The number of observations in each cell of the design is not the same, so this is an example of an unbalanced 2×2 design.
