Ch. 4- Understanding Research Studies: Mean & Standard Deviation
Use the information from the research study below to answer the questions:
Excerpt from the research study:
The authors assessed the short-term effectiveness of a Web-based alcohol education program on
entering freshmen. Study participants were incoming 1<sup>st</sup>-year students at a midsized, rural, elite,
private university in the Northeast. The researchers conducted a pre-test and post-test on both the
Control Group and the Intervention Group. The Intervention Group received the Web-based
alcohol education program.
Table 1
Pre- and Postintervention Knowledge Test Scores
Control group
test scores
Intervention group
test scores
Pre
Post
Pre
Post
$n$
M SD
M SD
M SD
M SD
All student participants 1,891 73.3 9.9 83.2 12.8 74.0 8.7 88.4 6.2
IN THIS STUDY:
1. On the average, which group had higher pretest scores?
2. On the pretest, which group had greater variability in their
scores?
3. On the posttest, which group had less variability in their
scores?
4. On the average, which group showed a greater gain from
pretest to posttest? Explain
ANSWER
