regression.linear.f: Power Analysis for Linear Regression: R-squared or R-squared...

In pwrss: Statistical Power and Sample Size Calculation Tools

Power Analysis for Linear Regression: R-squared or R-squared Change (F-Test)

Description

Calculates power or sample size (only one can be NULL at a time) to test R-squared deviation from 0 (zero) in linear regression or to test R-squared change between two linear regression models. The test of R-squared change is often used to evaluate incremental contribution of a set of predictors in hierarchical linear regression.

Formulas are validated using Monte Carlo simulation, G*Power, and tables in PASS documentation.

NOTE: The pwrss.f.reg() function and its alias pwrss.f.regression are deprecated, but they will remain available as a wrapper for power.f.regression() during the transition period.

Usage

power.f.regression(r.squared.change = NULL, margin = 0,
                   k.total, k.tested = k.total,
                   n = NULL, power = NULL, alpha = 0.05,
                   ceiling = TRUE, verbose = TRUE, pretty = FALSE)

Arguments

r.squared.change	R-squared (or R-squared change).
margin	margin - ignorable R-squared (or R-squared change).
k.total	integer; total number of predictors.
k.tested	integer; number of predictors in the subset of interest. By default m.tested = k.total, which implies that one is interested in the contribution of all predictors, and tests whether R-squared value is different from 0 (zero).
n	integer; sample size.
power	statistical power, defined as the probability of correctly rejecting a false null hypothesis, denoted as 1 - \beta.
alpha	type 1 error rate, defined as the probability of incorrectly rejecting a true null hypothesis, denoted as \alpha.
ceiling	logical; whether sample size should be rounded up. TRUE by default.
verbose	logical; whether the output should be printed on the console. TRUE by default.
pretty	logical; whether the output should show Unicode characters (if encoding allows for it). FALSE by default.

Value

parms	list of parameters used in calculation.
test	type of the statistical test (F-Test).
df1	numerator degrees of freedom.
df2	denominator degrees of freedom.
ncp	non-centrality parameter for the alternative.
null.ncp	non-centrality parameter for the null.
f.alpha	critical value.
power	statistical power (1-\beta).
n	sample size.

References

Bulus, M., & Polat, C. (2023). pwrss R paketi ile istatistiksel guc analizi [Statistical power analysis with pwrss R package]. Ahi Evran Universitesi Kirsehir Egitim Fakultesi Dergisi, 24(3), 2207-2328. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.29299/kefad.1209913")}

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

Examples

# in the outcome (R-squared = 0.15).
power.f.regression(r.squared = 0.15,
                   k.total = 3, # total number of predictors
                   power = 0.80)

# adding two more variables will increase R-squared
# from 0.15 (with 3 predictors) to 0.25 (with 3 + 2 predictors)
power.f.regression(r.squared.change = 0.10, # R-squared change
                   k.total = 5, # total number of predictors
                   k.tested = 2, # predictors to be tested
                   power = 0.80)

pwrss documentation built on Sept. 16, 2025, 9:11 a.m.