# Notation and symbols

∑ | Greek letter sigma, denoting sum of. ∑x is shorthand for $$ \sum_{i=1}^{n}{x_i} $$ |

| x | | absolute value of x |

α | probability of a Type I error; or level of hypothesis test, usually 0.05 |

β | probability of a Type II error |

χ^{2} | value from the Chi-squared distribution, see Chi-squared table |

CI | confidence interval |

CR | coefficient of repeatability |

DF | degrees of freedom |

F | value from the F-distribution, see F-Distribution critical values table |

K | kappa |

n or N | sample size |

P | probability of hypothesis |

r | Pearson correlation coefficient |

r_{s} | Spearman rank correlation coefficient |

R^{2} | coefficient of determination |

RSD | relative standard deviation |

s | standard deviation |

s^{2} | variance |

SD | standard deviation |

SEM | standard error of the mean |

t | value from the t-distribution, see t-distribution table |

z | value from the Normal distribution, see Normal distribution table |