Topic 8
DQ 1
To determine whether a new sleeping pill has an affect that varies with dosage, a researcher
randomly assigns adult insomniacs, in equal numbers, to receive either 4 or 8 grams of the
sleeping pill. The amount of sleeping time is measured for each subject during an 8-hour
period after the administration of the dosage. What type of design is this, and what type of
statistic is needed to analyze the data (consider ABAB studies)?
The research design described in the scenario is a randomized controlled trial (RCT) with a
between-subjects design. In this study, the independent variable is the sleeping pill dosage, with
two levels: 4 grams and 8 grams. The dependent variable is the amount of sleeping time
measured for each subject during an 8-hour period after the administration of the dosage.
Since participants are randomly assigned to either the 4-gram or 8-gram dosage group, this
design helps control potential confounding variables. It allows for investigating the specific
effects of the different dosages on sleeping time. A between-subjects analysis would be
appropriate to analyze the data from this study. One commonly used statistical test for
diagnosing the results of such a design is the independent samples t-test. The t-test would help
determine whether there are statistically significant differences in sleeping time between the two
dosage groups. Additionally, analysis of variance (ANOVA) could be employed if there are more
than two dosage levels to compare.
It's worth noting that "ABAB studies" usually refer to a different experimental design,
specifically a single-case experimental design used in behavioral research. In your scenario, the
focus is on a between-subjects design with two dosage levels, and the statistical analysis would
typically involve an independent samples t-test or ANOVA, depending on the study's complexity.
Reference
Tanious, R., De, T. K., Michiels, B., Van den Noortgate, W., & Onghena, P. (2020). Assessing
consistency in single-case ABAB phase designs.
Behavior Modification
, 44(4), 518-551.
https://journals.sagepub.com/doi/abs/10.1177/0145445519853793
DQ 2
Dr. Bill Board designs a 2 X 2 between-subjects factorial design, where Factor A is word
frequency (low or high) and Factor B is category cues (no cues or cues). Assume that the
data are interval. What type of statistic is needed to analyze the data?
Dr. Bill Board utilizes a 2 X 2 between-subjects factorial design, incorporating Factor A (word
frequency: low or high) and Factor B (category cues: no cues or cues) with interval data. In
analyzing this data, Dr. Bill would require a chi-square test, also denoted as χ2 test, a statistical
hypothesis test. This test assesses the likelihood that the observed distribution is due to chance,
