n.oneway: Calculates the required sample size for a one-way ANOVA.

Description Usage Arguments Value References Examples

Description

Calculates the required sample size for a one-way ANOVA.

Usage

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n.oneway(iv = iv, sig.level = 0.05, power = 0.8)

Arguments

iv

List of data for the treatment to be tested.

sig.level

Desired significance level (default is 0.05).

power

Desired level of power (default is 0.80).

Value

Returns the recommended sample size given the conditions to achieve the desired power.

References

Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Hillsdale, N.J.: Lawrence Erlbaum Associates.

Examples

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# Exercise 8.10, p.391 from Cohen (1988)
main.eff <- list(name = "Teaching", levels = 4, eta.sq = 0.0588)
# Running the function with default settings
n.oneway(iv = main.eff)

Example output

The following is the sample size recommendation to 
achieve a power of 0.80 at a significance level of 0.05.
Effect size used in calculation: Cohen's f
Cutoffs: small = 0.10, med = 0.25, large = 0.40

Treatment: Teaching
Effect Size (f): 0.250
Total N: 179
n per cell: 45

easypower documentation built on May 2, 2019, 2:18 a.m.