The last generation the article talks mainly about?

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

Standard deviation of 19,29,21,22,23

Aline passes through 3,7 and 6,9 what equation represents the line