﻿ VisualStat® Examples - One-Way Anova

Software to Simplify Statistical Practice ...

## One-Way ANOVA - Example

#### Analysis

1. Open the DataBook gear.vstz
open this data file via the Help / Open Examples menu; it is in the Sample Data
2. Choose the menu Analyze and the command One-Way, under group Analysis of Variance
3. In Variables, select diameter
4. In Grouping Variable, select batch
5. Click OK

#### Output

By default, R code is printed after parsing and before evaluation.

DataSheet is converted to DataFrame, in the form DataBook.DataSheet

```> ## Save variables.
> diameter <- gear.Sheet1\$diameter
> batch <- as.factor(gear.Sheet1\$batch)

> ## Fit one-way anova model.
> AnovaModel <- aov(diameter ~ batch)
> AnovaModel
Call:
aov(formula = diameter ~ batch)

Terms:
batch  Residuals
Sum of Squares  0.00072904 0.00317400
Deg. of Freedom          9         90

Residual standard error: 0.005938574
Estimated effects may be unbalanced

> summary(AnovaModel)
Df   Sum Sq   Mean Sq F value Pr(>F)
batch        9 0.000729 8.100e-05   2.297 0.0227 *
Residuals   90 0.003174 3.527e-05
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

> summary.vst(gear.Sheet1\$diameter , groups=gear.Sheet1\$batch, statistics=c('mean',
'sd','nrow'))
Statistic
Group   mean nrow          sd
1  0.9980   10 0.004346135
2  0.9991   10 0.005216427
3  0.9954   10 0.003977716
4  0.9982   10 0.003852849
5  0.9919   10 0.007578478
6  0.9988   10 0.009886017
7  1.0015   10 0.007877535
8  1.0004   10 0.003627059
9  0.9983   10 0.004137901
10 0.9948   10 0.005329165```