> For instance, in a series of three consecutive tests, the 13- inch model with the Touch Bar ran for 16 hours in the first trial, 12.75 hours in the second, an

> For instance, in a series of three consecutive tests, the 13- inch model with the Touch Bar ran for 16 hours in the first trial, 12.75 hours in the second, and just 3.75 hours in the third. The 13-inch model without the Touch Bar worked for 19.5 hours in one trial but only 4.5 hours in the next. And the numbers for the 15-inch laptop ranged from 18.5 down to 8 hours. How could this happen? Did each test follow the same process?