# visStatistics

Visualization of the statistical hypothesis test between two groups
of categorical or numerical data.

The function `visstat()`

**vis**ualizes the
**stat**istical hypothesis testing between two groups of
data, where `varsample`

is the dependent variable (or
response) and `varfactor`

is the independent variable
(feature). The statistical hypothesis test with the highest statistical
power and fulfilling the assumptions of the corresponding test is
performed and visualized. A graph displaying the raw data accordingly to
the chosen test as well as the test statistics is generated. Furthermore
`visstat()`

returns the corresponding test statistics as
text. The automated workflow is especially suited for browser based
interfaces to server-based deployments of R. Implemented tests:
`lm(), t.test(), wilcox.test(), aov(), oneway.test(),kruskal.test(), fisher.test(),chisqu.test()`

.

## Installation from GitHub

- Firstly, you need to install the devtools package. You can do this
from CRAN. Invoke R and then type
`install.packages("devtools")`

- Load the devtools package.
`library(devtools)`

- Install the package from the github- repository
`install_github("shhschilling/visStatistics")`

- Load the package
`library(visStatistics)`

- Help on the function usage
`?visstat`

## Examples

### Trees data set: Linear
regression

`visstat(trees,"Girth","Height")`

### Iris data set: Kruskal-Wallis
test

`visstat(iris,"Petal.Width", "Species")`

### InsectSprays data set: ANOVA

`visstat(InsectSprays,"count","spray")`

### InsectSprays data
set: Welch two sample t.test

`InsectSpraysAB <- InsectSprays[ which(InsectSprays$spray == 'A'| InsectSprays$spray == 'B'), ] #select only sprays 'A und 'B'`

`InsectSpraysAB$spray = factor(InsectSpraysAB$spray)`

`visstat(InsectSpraysAB,"count","spray")`

### ToothGrowth
data set: Wilcoxon rank sum test with continuity correction

`visstat(ToothGrowth,"len", "supp")`

#### HairEyeColor
data set: Pearsonâ€™s Chi-squared test

`HairEyeColorMale = counts_to_cases(as.data.frame(HairEyeColor[,,1]))`

`visstat(HairEyeColorMale,"Hair","Eye")`