Answer:
n = 4
Step-by-step explanation:
Where's a or did you mean n?
Answer:
The answer is below
Step-by-step explanation:
a) Given that the number of sample (n) = 300, therefore since n > 30, the distribution of the sample means is going to be normally distributed.
b) The mean of the distribution of sample means (also known as the Expected value of M) is equal to the population mean μ.

c) The standard deviation of the distribution of sample means is called the Standard Error of M, it is given by:

12 goes into 75 6 times with a remainder of 3. So the answer will be 6 remainder 3
Answer:
A sample of 18 is required.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Z-table as such z has a p-value of
.
That is z with a pvalue of
, so Z = 1.88.
Now, find the margin of error M as such
In which
is the standard deviation of the population and n is the size of the sample.
A previous study indicated that the standard deviation was 2.2 days.
This means that 
How large a sample must be selected if the company wants to be 92% confident that the true mean differs from the sample mean by no more than 1 day?
This is n for which M = 1. So



Rounding up:
A sample of 18 is required.