LR.pvalue: P-values based on LR statistics for 2 x 2 Tables

In ProfileLikelihood: Profile Likelihood for a Parameter in Commonly Used Statistical Models

P-values based on LR statistics for 2 x 2 Tables

Description

This function provides p-values based on likelihood ratio (LR) statistics for 2 x 2 tables.

Usage

LR.pvalue(y1, y2, n1, n2, interval=0.01)

Arguments

y1	the number of success for treatment 1.
y2	the number of success for treatment 2.
n1	the sample size for treatment 1.
n2	the sample size for treatment 2.
interval	grid for evaluating a parameter of interest to obtain values for likelihoods. The default is 0.01.

Details

This function provides p-values based on the profile and conditional likelihood ratio (LR) statistics for 2 x 2 tables. The function also provides the profile and conditional likelihood support intervals (k=6.8) corresponding to a 95% confidence interval based on a normal approximation. For comparison purpose, p-values from Pearson's Chi-squared test, Fisher's exact test and Pearson's Chi-squared test with continuity correction are also provided.

Value

mle.lor.uncond	the maximum likelihood estimate for log odds ratio.
mle.lor.cond	the maximum conditional likelihood estimate for log odds ratio.
LI.norm.profile	profile likelihood support interval (k=6.8) corresponding to a 95% confidence interval based on a normal approximation.
LI.norm.cond	conditional likelihood support interval (k=6.8) corresponding to a 95% confidence interval based on a normal approximation.
LR.profile	profile likelihood ratio.
LR.cond	conditional likelihood ratio.
Pvalue.LR.profile	p-value based on the profile LR statistic.
Pvalue.LR.cond	p-value based on the conditional LR statistic.
Pvalue.chisq.test	p-value from Pearson's Chi-squared test.
Pvalue.fisher.test	p-value from Fisher's exact test.
Pvalue.chisq.cont.correction	p-value from Pearson's Chi-squared test with continuity correction.

Warning

Likelihood intervals, LRs and the corresonding p-values are not reliable with empty cells (y1=0 or y2=0) in 2 x 2 tables.

P-values from Pearson's Chi-squared test, Fisher's exact test and Pearson's Chi-squared test with continuity correction are provided only for comparison purpose. For more options, use chisq.test and fisher.test for these tests.

Author(s)

Leena Choi <[e-mail]>

See Also

profilelike.plot, profilelike.summary, profilelike.glm

Examples

	(fit <- LR.pvalue(y1=20, y2=30, n1=50, n2=50, interval=0.01))

ProfileLikelihood documentation built on Aug. 25, 2023, 5:15 p.m.