Use the AVERAGEIFS function to get the average (mean) of certain row(s) in the table, based on a condition (or more)

The syntax is:

AVERAGEIFS(column_to_retrieve_value_from, column_to_search, condition [, default_message])

AVERAGEIFS(T1!A, T1!B, ">5", 'No Results Found')

will return the average (mean) of all the values in column A of table T1 for which the corresponding value in table T1 column B is greater than 5
so for the table:

100 | 2 |

200 | 10 |

300 | 20 |

400 | 30 |

You can also have multiple conditions:

AVERAGEIFS(T1!A, T1!B, ">10", T1!C, 3)

This will return average (mean) of the values in column A for which the value in column B is greater than 10 and the value in column C is 3.
See the Tables page for more tips on how to work with tables.