evidence (version 0.8.10)

B2Nsir: Bayesian analysis of the means of two Normal samples using SIR priors.

Description

Produces exploratory plots (boxplots and, if the sample sizes are equal), a quantile-quantile plot of the two samples. Also produces Bayesian posterior densities of the two sample means and of the difference between the means. The priors used are standard improper reference priors.

Usage

B2Nsir(formula, data, var.equal = TRUE, alpha = 0.05, plotit = TRUE, r = 10000)

Arguments

formula

the standard formula interface: response ~ factor

data

a data.frame containing the response and the two-level factor

var.equal

if TRUE the group variances are assumed to be equal, if FALSE two separate group variances are estimated

alpha

1 - level of credibility, so that for alpha = 0.05 (the default) credible intervals will have 95% credibility

plotit

should plots be produced?

r

the number of samples from the posterior distribution; can usually be left at its default value of 10000

Value

none returned; the function produces several plots and prints some statistics.

Details

Note that in the first plot the second sub-plot is NOT a normality plot but a quantile-quantile plot that compares the observations in the two groups.

References

van Hulst, R. 2018. Evaluating Scientific Evidence. ms.

See Also

BnNsir

t.test

Examples

# NOT RUN {
data(bodytemp)
B2Nsir(temperature ~ gender, bodytemp)
# }