After Careful Ethical Review of Planned Procedures, a Researcher Tests

question 59

Multiple Choice

After careful ethical review of planned procedures, a researcher tests a new brain activation drug by taking a sample of 50 volunteers and randomly assigning 25 participants to the treatment condition and 25 to the control (placebo) condition.She then carries out an fMRI scan to assess the level of activation in regions of the participants' brains 30 minutes after administering the drug.She carries out a between-participants t-test in SPSS which provides the output shown below: What further advice is appropriate to give the researcher here?

• A)The variances look as if they could be unequal.
• B)It is worth ensuring that the distributions of the scores are normal.
• C)The negative confidence interval suggests she needs to reduce statistical uncertainty further.
• D)The t-test should be accompanied with a measure of effect size such as Cohen's d.
• E)Both (a)and (d).

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Definitions:

Chi-square Test

A statistical test used to determine if there is a significant difference between the expected frequencies and the observed frequencies in one or more categories.

Distribution

Refers to the way in which something is shared out or spread across a range, often used in reference to statistical data.

Two Variables

Refers to studies or analyses that involve examining the relationships or interactions between two different variables.

Test of Independence

A statistical technique that identifies whether there is a meaningful relationship between two variables of categorical type.