Measuring and data collection

Choosing a statistical test

Minimum sample size

Not normally distributed

Statistical process control (SPC)

For commersial use

75 EURO

When choosing a statistical test it is important that you known what you want to test. When doing a specific statistical test and it is significant it is important to verify the shape and and the sample size. For more information what are the restrictions of each test see the specific page of the test.

- Mean/Median
- Variation
- Linear relations
- Reliability failure rate
- Shape of distribution
- Analysis of a measurement system
- Overview

- Normal Distribution one sample t-test
- Not Normal Distribution 1 sample Wilcoxon median test

- Normal Distribution 2 sample t-test
- Not Normal Distribution 1 sample Wilcoxon median test

- Normal Distribution One way Anova
- Not Normal Distribution Kruskal-Wallis Test

- Normal Distribution Variation F-test
- Not Normal Distribution Variation Levene test

- Normally and Not Normal Distribution Variation Levene test

- Correlation calculates if there is a relation
- Regression calculates what the relations is between the data-sets

- multiple correlation coefficient calculates if there is a relation
- Multiple linear regression calculates what the relations is between the data-sets

- Beta know small sample size Weibayes
- Big samples size Weibull analysis (n>20)

- Non Destructive testing Crossed Gauge R&R
- Destructive testing Nested Gauge R&R (destructive)

Test what | Normal Distribution | With what statistical test |

Difference in Mean/Median | Yes | t-test |

No | Wilcoxonâ€“Mannâ€“Whitney-test | |

Difference in Mean/Median between multiple data sets | Yes | One way Anova |

No | Kruskal-Wallis Test | |

Difference in Variation | Yes | Variation F-test |

No | Variation Levene test | |

If data set is normal distributed | n.a. | Anderson Darling normality test |

Is the data according specification | Yes | Cp Cpk % out of tolerance |

If there is relation between two data sets | n.a. | Correlation |

Calculates the relation between data sets | n.a | Regression |

Difference in two proportions (Data set with only good or false results) | n.a. | Proportions |