Answer: 0.6065
Step-by-step explanation:
Given : The machine's output is normally distributed with
Let x be the random variable that represents the output of machine .
z-score :
For x= 21 ounces
For x= 28 ounces
Using the standard normal distribution table , we have
The p-value :
Hence, the probability of filling a cup between 21 and 28 ounces= 0.6065