Solution: We are given the population mean 
Now, in order to find which shift's mean is closest to population mean, we will find the mean of each shift.
The mean of shift 1 is:

The mean of shift 2 is:

The mean of shift 3 is:

The mean of shift 4 is:

We clearly see the mean of shift 2 is close to the population mean. Hence the option B) Shift 2 is correct.
Answer:
Step-by-step explanation:
This question is about the benefits of estimation.
1300/13 is easy and results in 100.
1287/13 can be approximated by 1300/13: 1287/13 ≈ 100.
Actually, 1287 = 1300 - 13 = 13(99); just subtract 1 from 100.
So: 1287/13 = 1300 - 13 = 1287. A nice bit of mental math!
Answer:
4/13 is the answer
total = 4+3+5+1= 13
let a be the event of getting red marbles= total is 4
probability=4/13