The formula for this is 
. If the diameter is 8 the radius is 4, so filling in accordingly we have 
and 
which is 
and when you multiply in 3.14 you get that A = 401.92 or B above.
Want two numbers multiply to get -30 and add to get -13
1 answer:
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Answer:
(47.3, 54.1)
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 .
That is z with a pvalue of , so Z = 1.96.
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.
The lower end of the interval is the sample mean subtracted by M. So it is 50.7 - 3.4 = 47.3
The upper end of the interval is the sample mean added to M. So it is 50.7 + 3.4 = 54.1
The answer is (47.3, 54.1).