1. A researcher is interested in whether a new medication will reduce anxiety fo

Question

1. A researcher is interested in whether a new medication will reduce anxiety for those who are diagnosed with generalized anxiety disorder. He is concerned with placebo effect. He is also concerned with regression to the mean which can occur when the sample experiences a reduction in symptom intensity due to natural symptom fluctuation with time rather than due to a treatment. He decides to assess this with one client at a time. He has client 1 take a pretest of anxiety. Then, client 1 is put on the medication for 4 weeks and completed the anxiety measure again. Next, client 1 is given placebo for 4 weeks and is assessed again. Finally, client 1 is put back on the medication and is assessed for anxiety one more time.

Which design best matches the one described here?

d. ABAB single-case experimental design

2.

A developmental psychologist has just completed some of her research on abstract reasoning and age. However, she had an issue with her data. She started the study with 100 children two years ago but say a 20% attrition rate in this sample over the years. She decides to address this by identifying two groups within her sample-those who were still participating at the end (completers) and those who were not (non-completers). Then, she decides to compare data from the start of the study (when everyone was still present and provided baseline data) and see if scores at the beginning were different in those who ended up being completers compared to non-completers. She uses a statistical test to compare mean scores for completers compared to non-completers and finds no significant difference. This shows that the two groups are similar and that there are no issues with using only the completers for further analyses. Therefore, she includes these results to justify doing all tests of the hypothesis with the sample of completers only.

Based on this description, which statistical test did she most likely use to compare the scores of completers and non-completers?

Explanation / Answer

1.d. ABAB single-case experimental design

2.d.dependent samples t-test

The dependent t-test compares the means of two related groups to determine whether there is a statistically significant difference between these means.It is also called the paired t-test or paired-samples t-test. Whereas independent-samples t-tests compare scores on the same variable but for two different groups of cases.

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