PSYCO 212 Active Learning Worksheet
Chapter #11: Confounding and Obscuring Variables
TV ads promote online “brain games” and learning tools for adults and kids. A researcher decided
to test the effectiveness of one of these games, ABCmouse. She gave kids aged 3–5 experience with
either ABCmouse or an alternative game that wasn’t educational (Pig Pile). After giving kids 2 weeks of
experience playing their respective game, she tested their reading ability using the Burt Reading Test,
which tests how many of 110 words a child can read. The words are graded in order of difficulty, so the
more words children can read, the better their score. She was able to use students at a large, public
preschool as participants. All the kids were aged 3 to 5.
Below are eight descriptions of variations on the study described above. Read each description and:
a. Draw a sketch of each design, using the diagrams in Chapter 10 as a guide (e.g., Fig. 10.9, 10.14, etc.).
Draw a sketch of the study’s results, too, using a bar graph or line graph.
b. Identify the design as pretest-posttest, posttest only, repeated measures, concurrent measures, or one
group, pretest-posttest. Be sure your graph depicts the data appropriately for the design.
c. Identify the threats to internal validity in each design. Many of the following eight descriptions involve
threats to internal validity from Table 11.1. Identify each one, name the threat, and explain how internal
validity is threatened. Some examples illustrate more than one threat, but usually I have only one in mind
as the main threat. Also, at least one example has no threats.
1. As it turned out, the Pig Pile game was considered inappropriate for school use by many of the
teachers. Therefore, the researchers simplified their study. Early in the spring, the kids in three targeted
classrooms were tested on the Burt Reading Test (the mean of the 36 kids in the study was 12.0). Then,
during school hours, research assistants (RAs) introduced the ABCmouse game to each child who had
permission to participate. For the next 2 weeks, during each morning’s play period, kids were required to
play with this game for 10 minutes. At the end of this 2-week period, the Burt Reading Test was
administered by a new RA. The mean reading score of the 36 kids had risen to 25, a statistically
significant gain. The researchers concluded that ABCmouse improved kids’ ability to read words.