question archive A researcher is testing the effectiveness of a new herbal supplement that claims to improve physical fitness
A researcher is testing the effectiveness of a new herbal supplement that claims to improve physical fitness
Subject:MathPrice: Bought3
A researcher is testing the effectiveness of a new herbal supplement
that claims to improve physical fitness. A sample of n = 16 college students is obtained and each student takes the supplement daily for six weeks. At the end of the 6-week period, each student is given a standardized fitness test and the average score for the sample is M = 39.
1) If we know for the general population of college students, the distribution of test scores is normal with a mean of µ = 34 and a standard deviation of σ = 9. Do students taking the supplement have significant effect on fitness scores? α = .05.
2) Following 1), compute the Cohen's d to estimate the size effect.
3) If we don't know population's standard deviation, only know population mean µ = 34, but we measured sample's standard deviation is s=10, does the supplement have significant effect on fitness scores? α = .05.
4) Following 3), calculate the estimated d and r2 , the percentage of variance accounted for, to measure the size effect.
