Question

A researcher wants to test her hypothesis that drinking caffeine while learning a new skill will aid in developing that skill. In order to test her hypotheses, she recruits a sample of 25 beginner piano students from a nearby college (n = 25). Each piano player is given a new song to learn and asked to drink a large coffee each time they sit down to practice it over a 6 week span of time. Afterward, when the six weeks are up, they are asked to perform the song for an instructor who rates their progress using a standardized scoring system. For the general population of beginner piano players, scores using this system are normally distributed with a mean (or μ) of 70 and a standard deviation (or σ) of 15. For this particular group of 25 caffeine-drinking beginner piano players, the mean score was 75.

4. Is the data here sufficient to conclude that caffeine had an effect on new skill development? Use a twotailed test with α = .05 to draw your conclusion.

5. Compute Cohen’s d for this study.

Answer 1