Answer:
The minimum sample size needed is
. If n is a decimal number, it is rounded up to the next integer.
is the standard deviation of the population.
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 = 1.645.
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.
How large a sample must she select if she desires to be 90% confident that her estimate is within 4 ounces of the true mean?
A sample of n is needed, and n is found when M = 4. So






The minimum sample size needed is
. If n is a decimal number, it is rounded up to the next integer.
is the standard deviation of the population.
Answer:
N = 52 * (9/7)^(t/1.5)
Step-by-step explanation:
This problem can be modelated as an exponencial problem, using the formula:
N = Po * (1+r)^(t/1.5)
Where P is the final value, Po is the inicial value, r is the rate and t is the amount of time.
In our case, we have that N is the final number of branches after t years, Po = 52 branches, r = 2/7 and t is the number of years since the beginning (in the formula we divide by 1.5 because the rate is defined for 1.5 years)
Then, we have that:
N = 52 * (1 + 2/7)^(t/1.5)
N = 52 * (9/7)^(t/1.5)
Answer:
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Step-by-step explanation: