Simplify 15-7 2 using order of operations

In a column proof the right column states your reasons

The birth weights of newborn babies in the unites states follow in a normal distrubution with a mean of 3.4 kg and standard deviation of 0.6 kg. reaserches interested in studying how. children gain weights decide to take random samples of 100 newborn babies and calculate the sample mean birth weights for each sample

On the first of each month sasha runs a 5k race she keeps track of her times to track her progress her time in minutes is recorded in the table