This function calculates parametric CIs for the population R-squared.
It is based on CIs for the non-centrality parameter Delta of the F distribution,
found by test inversion. Delta values are mapped to R-squared by
R-squared = Delta / (Delta + df1 + df2 + 1), where df1 and df2 are the degrees
of freedom (df) of the F test statistic.
A positive lower (1-alpha)*100%-confidence limit for the R-squared goes
hand-in-hand with a significant F test at level alpha.
An object of class "cint" containing these components:
parameter: Parameter specification.
interval: CI for the parameter.
estimate: Parameter estimate.
probs: Lower and upper probabilities.
type: Type of interval.
info: Additional description.
Arguments
x
The result of stats::lm() or the F test statistic.
df1
The numerator df. Only used if x is a test statistic.
df2
The denominator df. Only used if x is a test statistic.
probs
Lower and upper probabilities, by default c(0.025, 0.975).
Details
According to ?stats::pf, the results might be unreliable for very large F values.
Note that we do not provide bootstrap CIs here to keep the input interface simple.
References
Smithson, M. (2003). Confidence intervals. Series: Quantitative Applications in the Social Sciences. New York, NY: Sage Publications.