Answer: -1.33 .
Step-by-step explanation:
Formula to find the Z-score :

Given: Mean = 191 and Standard deviation = 21
Then , the z-score corresponding to the expected value of 163 will be :

Hence, the z score corresponding to selling 163 inhalers is -1.33 .
Check the attached file for the answer.
Answer:
This means that we are 80% confident that the mean of the drive-through service time is between 178.0 seconds and 181.0 seconds. This conclusion was obtained after examined 576 customers. If you want a greater % of confidence you will have to lower the lower bound and increase the upper bound
Answer:
To find the average rate of change, we divide the change in the output value by the change in the input value.
Step-by-step explanation: