Unit 2, Question 9

Is this a one-tailed or two-tailed test? If it is a one-tailed test, are we looking at the right or left tail? Explain your answer.

Scenario:

Although there is a popular belief that herbal remedies such as Gingko biloba and Ginseng may improve learning and memory in healthy adults, these effects are usually not supported by well-controlled research (Persson, Bringlov, Nilsson, & Nyberg, 2004). In a recent study, a researcher obtained a sample ofn = 16 participants and had each person take the herbal supplement every day for 90 days. At the end of the 90 days, each person took a standardized memory test. For the general population, the scores on this memory test form a normal distribution with a = 50 and = 12. The sample of research participants had an average score of M = 54.

Research Question:

Did the use of herbal supplements lead to improvements in memory?