# Elementary Statistics

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1) Construct a confidence interval of the population proportion at the given level of confidence.
x=60,n=300, 99% confidence.
The 99% confidence interval is (_,_)

2) A researcher wishes to estimate the proportion of adults who have high-speed internet access. What size sample should be obtained if she wishes the estimate to be within 0.04 with 99% confidence if
a) she uses a previous estimate of 0.52?
b) she does not use any prior estimates?

• Elementary Statistics (Partial) -

1. 99% = mean ± 2.575 SEm

SEm = SD/√n

What is the value of the standard deviation (SD)?

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