Answer:
5.2
Step-by-step explanation:
ok so we need to find the unit rate( how many customers per minute) and thats 12 divided by 9 which is 1.3 minutes per customer so now we need to find what 1.3 minutes is x4 customers. This brings us to 5.2.
Answer:
The mean of of the sample mean of these quality checks is 10 and the standard deviation is 0.7155.
Step-by-step explanation:
To solve this question, we use the central limit theorem.
The Central Limit Theorem estabilishes that, for a random variable X, with mean
and standard deviation
, the sample means with size n can be approximated to a normal distribution with mean
and standard deviation 
In this problem, we have that:

The mean of of the sample mean of these quality checks is 10 and the standard deviation is 0.7155.