Question 2:

Experimenter bias refers to the presence of inadvertent cues that lead to results consistent with the researcher's expectations that have nothing to do with the treatment effect. To test for the presence of experimenter bias, student participants are given caffeine prior to taking an arithmetic test. One group of students are told that caffeine should lead to a good performance while another group is told that caffeine should lead to a poor performance. The dependent variable is the number of problems answered correctly in 2 minutes. Here are the results:

Good Performance	Poor Performance
19 16 23 13 18 15 20 25 22	14 18 17 12 21 16 24 14

a) Conduct the appropriate inferential test to determine whether or not experimenter bias had an effect (use a directional hypothesis with ).?

Step 1: Hypotheses

Step 2: Decision Criterion

Step 3: Obtain a Statistic

Step 4: Make a Decision

Step 5: Report the Result

b) Use Cohen's d to report and interpret an effect size for the test. (5 marks)

c) Construct the 95% confidence interval. How would you interpret this interval?

d) Should we be concerned that the inferential test conducted in this question might be biased? Explain why or why not

This was all that was provided in the question.