Hypothesis testing

A researcher would like to examine how the chemical tryptophan, contained in foods such as turkey, can affect mental alert ness. A sample of n = 9 college students is obtained, and each student's performance on a familiar video game is measured before and after eating a traditional Thanksgiving dinner including roast turkey. The average score dropped by MD = 14 points after the meal with 58 = 1152 for the difference scores. 1. Is there a significant difference in performance before eating versus after eating? Use a twotailed test with a = .05. Show all calculations. a. State the research hypotheses b. Identify the critical value c. Calculate the test statistic d. Evaluate the null hypothesis