quantchem (version 0.13)

dstat: Descriptive statistics of quantitative analysis results

Description

Performs comprehensive statistical evaluation of quantitative analysis results.

Usage

dstat(x, expected = median(unlist(x)), sort = TRUE, inverse.f = TRUE, na.rm = FALSE, conf.level = 0.95, alternative = c("two.sided", "less", "greater"), ansari = FALSE)

Arguments

x
a vector of results, of a dataframe with results to compare
expected
expected reference value
sort
if TRUE, the matrices are sorted by means, variances or p-values.
inverse.f
if F value in variance comparison is below 1, the inverse is taken (has no effect on p-value, but there are sometimes need to have such F
na.rm
logical: should NA values be removed?
conf.level
level for calculate confidence intervals
alternative
alternative for all tests performed.
ansari
due to reports of errors on some datasets, the ansari.test() on data is turned off by default since 0.12. you can turn it on by setting this variable to TRUE

Value

A list containing following matrices (if data is a vector, only 5 first are returned):
mean
mean, its confidence interval and t-test for expected value
median
median, its confidence interval and Wilcoxon test for expected value
var
variance, standard deviation, standard error and Dixon test for outlier
rsd
relative standard deviation, its confidence interval and Grubbs test for outlier
range
minimum and maximum value, range, IQR, MAD and Shapiro-Wilk test for normality
vartest
ratios of variances, their confidence intervals and F test with p-value
ttest
differences between means, their confidence intervals and t test with p-value
atest
nonparametric differences in scale, their confidence intervals and Ansari-Bradley test with p-value
atest
nonparametric differences in location, their confidence intervals and Wilcoxon test with p-value
anova
ANOVA between all data
kruskal
Kruskal-Wallis test (nonparametric equivalent for ANOVA)
bartlett
Bartlett test for homogeneity of all variances
fligner
Fligner-Killeen test for equal variances (nonparametric alternative to Bartlett)

Details

If argument is vector, several one-row matrices are produced (see below). If argument is a data.frame, there are also additional matrices with pairwise comparisons. The comparison of all groups by appropriate test are also calculated. This function prints its results with significance stars and returns a list invisibly.

See Also

vstat

Examples

set.seed(1234)
a = data.frame(x=rnorm(10),y=runif(10),z=rt(10,1))
dstat(a,0)