two.sample.mean {intervcomp}

Range-Preserving Two-Sample T-Test for Equality of Means

Description

Range-preserving two-sample t-test for comparing means.

Usage

two.sample.mean(x, y, transformation = c("none", "log", "logit"),
  alternative = c("two.sided", "less", "greater"), paired = FALSE,
  alpha = 0.05, plot.ci = TRUE, plot.ici = TRUE,
  ici.interval = NULL, add.individual.ci = TRUE, by.ici = 0.5,
  xlab.ici = "", rounds = 3, rounds.plot = NULL,
  ci.interval = NULL, by.ci = 0.5, name.x = NULL, name.y = NULL,
  pool.mean = FALSE, logit.interval = NULL, rho = NULL,
  tol = 1e-07)

Arguments

x

A vector specifying the first sample.

y

A vector specifying the second sample.

transformation

A character string specifying the transformation on the sample means; "none" for real-valued data, "log" for positive-valued data, and "logit" for data in a fixed interval. The default option is "none".

alternative

A character string specifying the alternative hypothesis; "two.sided" for two-tailed, "less" for left-tailed, and "greater" for right-tailed alternative hypothesis. The default option is "two.sided".

paired

A boolean specifying whether or not the samples are paired or independent. The default option is FALSE.

alpha

A numeric specifying the significance level. The default option is 0.05.

plot.ci

A boolean specifying whether or not the deviation between the two samples should be plotted. The default option is TRUE.

plot.ici

A boolean specifying whether or not the inferential confidence intervals for the two samples should be plotted. The default option is TRUE.

ici.interval

A vector with two elements specifying the range of values for the plot of inferential confidence intervals. The default option is NULL, in which case, an appropriate range is automatically specified.

add.individual.ci

A boolean specifying whether or not the confidence intervals with the confidence level implied by alpha should also be plotted. The default option is TRUE.

by.ici

A numeric specifying te scales in the plot for ici.interval. The default option is 0.5.

xlab.ici

A character string specifying the x axis labels used for the inferential confidence intervals and confidence intervals. The default option is "".

rounds

A numeric specifying the number of decimal places to be rounded. The default option is 3.

rounds.plot

A numeric specifying the number of decimal places to be rounded. The default option is NULL, in which case it is set equal to rounds.

ci.interval

A vector with two elements specifying the range of values for the plot of confidence intervals. The default option is NULL, in which case, an appropriate range is automatically specified.

by.ci

A numeric specifying te scales in the plot for ci.interval. The default option is 0.5.

name.x

A character string specifying the label for the x variable. The default option is NULL, in which case, it is set to "x".

name.y

A character string specifying the label for the y variable. The default option is NULL, in which case, it is set to "y".

pool.mean

A boolean specifying whether or not the sample means should be pooled for the degrees of freedom. The default option is FALSE.

logit.interval

A vector with two elements specifying the lower and upper bound if logit transformation is used. The default option is NULL.

rho

A numeric specifying the correlation coefficient between the two samples. The default option is NULL, in which case, the sample correlation coefficient is estimated automatically.

tol

A numeric specifying the cut-off value for a numerical zero. The default option is 1e-7.

Value

CI

A data frame displaying the effect size estimate, lower and upper bound of the effect size confidence interval, and the degrees of freedom.

ICI

A data frame displaying the sample mean for both x and y, lower and upper bounds of the inferential confidence intervals, the degrees of freedom of the inferential confidence intervals, the inferential significance level, and the significance level.

Statistic

A data frame displaying the test statistic and p-value of the generalized two-sample t-test.

Ind.CI

A data frame displaying the sample mean for both x and y, lower and upper bounds of the individual confidence intervals, the degrees of freedom of the individual confidence intervals, the sample standard deviations, and the significance level.

Effect.Sizes

A data frame displaying Cohen's d and either log ratio (for transformation="log") or log odds (for transformation="logit").

Examples

 set.seed(123)
 x<-runif(10)
 y<-runif(15)
 two.sample.mean(x,y,"logit","two.sided",paired=FALSE, ici.interval=c(0,1),
  by.ici=0.2, logit.interval=c(0,1), rounds=2, name.x="xvar", name.y="yvar")