The area of a circle is 132.7 square cm. Find the diameter.
2 answers:
Answer:
13
Step-by-step explanation:
To find the diameter, use the diameter formula.
d = 2r (r = radius)
In this case, we don't have a radius so to find the radius, use the radius formula.
r = (A = area)
So, r = square root of 132.7/pi
r is approximately 6.5
Now we have the radius so we can find the diameter:
d = 2(6.5)
d = 13
Diameter is 13
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Answer:
A sample size of 1031 is required.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is of:
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This means that
98% confidence level
So , z is the value of Z that has a pvalue of
, so
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You would like to be 98% confident that your estimate is within 3.5% of the true population proportion. How large of a sample size is required?
A sample size of n is required.
n is found when M = 0.035. So
Rounding up:
A sample size of 1031 is required.