If the population quadruples every period say hour, that means the "rate of growth" is 300%, so whatever the current amount, increased by 3 times as much is 4 times the current amount, or a quadrupled amount.
Mean -to-MAD ratio is the division of the Mean by the Mean Absolute Deviaion (MAD). For the set 1, mean / MAD is 10.3 / 1. 6 = 6.4375; and for the set 2, Mean / MAD is: 12.7 / 1.5 = 8.467. This is a measure of disperssion of a set of values. MAD is calculated as the sum of the absolute differences of the values and the mean.
30 because 5x6= 30. All you have to do if the fractions are already simplified, is multiply the denominators together.
