Comparing two arrays of data

Hi there!This isn't really a "question" per se, I'm just hoping to hear a few ideas from people. Let's suppose I have two different arrays (say 4 x 4, for argument's sake). What methods could I use to compare how "similar" these arrays are?For example:3 | 4 | 7 | 2 |

12 | 3 | 44 | 7 |

14 | 25 | 6 | 9 |

19 | 8 | 8 | 5 |

2 | 7 | 9 | 4 |

2 | 3 | 33 | 16 |

9 | 11 | 7 | 2 |

3 | 20 | 6 | 14 |

My first thought was to make a third table containing the absolute values of the differences between the two tables, as follows:1 | 3 | 2 | 2 |

10 | 0 | 11 | 9 |

5 | 14 | 1 | 7 |

16 | 12 | 2 | 9 |

The above entries sum to 104, and dividing this by the number of entries (16) yields 6.5. So I can say that "on average, the values in table B differ from those in table A by 6.5".Another thought I had was to square the differences between the two tables, then sum these squared differences, then divide this total by n (16), then take a square root. For the above tables this yields 8.20061.Basically I want to compare lots of different tables and say which ones are more "like" others than others. If that makes sense!Does anyone have any better suggestions than what I've written above? (Nod)