The number of chocolate chips in an 28 once bag of chocolate chips is approximately normally distributed with a mean of 1252 chips and standard deviation 129 chips. what is the probability that a randomly selected bag contains between 1100 and 1500 chocolate chips, inclusive, is

The probability is about 85.29%.

To do this, you need to first find the z-score on each end of the interval. Then, you can subtract the percents to find the percent in the middle.

Lower:
(1000 - 1252) / 129 = -1.18 which gives a probability of 11.9%

Upper:
(1500 - 1252) / 129 = 1.92 which gives a probability of 97.19%

97.19 - 11.9 = 85.29