A farmers field is 32 feet on each side. How many square feet does she have to plow?
1 answer:
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Answer:
C. [21.80, 22.80]
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 Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find M as such
In which is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 22.3 - 0.5 = 21.8 hours.
The upper end of the interval is the sample mean added to M. So it is 22.3 + 0.5 = 22.8 hours
So the correct answer is:
C. [21.80, 22.80]