Answer: 99.7 % of the bags contain between 62 and 86 potato chips.
Explanation:
The standard deviation given is 4.
Find the difference between the given numbers and the mean,
74-62= 12 . 86-74=12
then divide 12 by 4 to find the number of standard deviations: 12/4=3
Check a chart or diagram of the Gaussian Distribution to find that 99.7% of the samples lie within 3 standard deviations from the mean.