5^2 x 5^2 20 80 625 425

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

Answer for 10 points show work you guys in advanced < 3

How can you find the mean absolute deviation (mad) for this set of data?