Part 1:
1. Calculate the sample size needed given these factors:
The factors given for calculating the sample size are as follows:
one-tailed t-test with two independent groups of equal size small effect size = 0.2 alpha = 0.05 beta = 0.2 Power = 1 – beta = 1 – 0.2 = 0.8
Using the priori function:
Using the priori function on GPower, the sample size based on the factors above was determined. The results of the analysis are as shown below.
Results:
t tests - Means: Difference between two independent means (two groups)
Analysis: A priori: Compute required sample size
Input: Tail(s) = One Effect size d = 0.2 α err prob = 0.05 Power (1-β err prob) = 0.8 Allocation ratio N2/N1 = 1 Output: Noncentrality parameter δ = 2.4899799 Critical t = 1.6473230 Df = 618 Sample size ...
