# Calculate the sample size needed given these factors

August 30, 2017

uestion
1. Calculate the sample size needed given these factors:

one-tailed t-test with two independent groups of equal size
small effect size (see Piasta, S.B., & Justice, L.M., 2010)
alpha =.05
beta = .2
Assume that the result is a sample size beyond what you can obtain. Use the compromise function to compute alpha and beta for a sample half the size. Indicate the resulting alpha and beta. Present an argument that your study is worth doing with the smaller sample.
2. Calculate the sample size needed given these factors:

ANOVA (fixed effects, omnibus, one-way)
small effect size
alpha =.05
beta = .2
3 groups
Assume that the result is a sample size beyond what you can obtain. Use the compromise function to compute alpha and beta for a sample approximately half the size. Give your rationale for your selected beta/alpha ratio. Indicate the resulting alpha and beta. Give an argument that your study is worth doing with the smaller sample.

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