will not argue that all people suffering from the disorder should be treated in
this way but rather will use the case study to suggest treatment programs othertherapists might explore with their clients. A therapy procedure is most effec-
tively demonstrated when the client ’s progress is compared at various stages
of the treatment, such as comparing a no-treatment period with a treatment
stage.
Finally, an investigator might choose the case study method simply to dem-
onstrate possibilities. For example, a researcher using one or two easily hypno-tizable people might demonstrate impressive changes in behavior. Some deeply
hypnotizable people have been reported to change skin temperature on one
part of the body but not on another or to form blisters on their hands whenimagining their hands are on fire. These studies are not intended to argue that
all people are able to do these things but rather to illustrate some of the possibil-
ities obtainable with hypnosis.
STATISTICAL ANALYSIS OF DATA
Suppose a waitress wants to know, for obvious reasons, what kind of behav-ior elicits the largest tips from customers. Her hypothesis is that smiling andacting in a friendly manner will result in better tips than acting in a more pro-
fessional and reserved manner. She tests her hypothesis by alternating be-
tween the friendly and professional styles each night for 14 nights. At the
end of each evening, she counts her tips and records the data. Suppose these
are her findings:
Friendly Approach Professional Approach
$41.50
$46.90
52.75 41.75
49.60 48.00
42.00 42.25
51.10 43.60
39.45 49.30
40.20 40.60
$45.23 average $44.63 average
The waitress concludes that the friendly approach indeed works best, and
she
changes to a friendly waitressing style from then on. But is her conclusion
justified? We can see from the numbers that the friendly style came up with a
higher average tip than the professional style. But by now you probably have
already wondered if an average of $45.23 is reliably different from an aver-
age of $44.63. Because of naturally occurring variation in the amount of tipsmade in an evening, we would not expect the averages to come out exactly
the same, even if the waitress never changed her style. One condition in this
study would almost always come out at least a little higher than the other.30 CHAPTER 2 Personality Research Methods