A researcher wants to know if eating fish high in Omega 3 fatty acids improves concentration. The mean score on a concentration task (solving math word problems) the population is = 100 with a standard deviation of sigma = 16. A sample of 50 people are instructed to each 5 servings of fish per week for one month. At the end of the month the mean concentration score for the sample was M = 104. What is the independent variable (IV) and dependent for this study