Question

1. Express the confidence interval 86.5%±4.6% in interval form

2. Assume that a sample is used to estimate a population proportion p. Find the margin of error M.E. that corresponds to a sample of size 217 with 23% successes at a confidence level of 80%.

M.E. = %

3.A political candidate has asked you to conduct a poll to determine what percentage of people support her.

If the candidate only wants a 6% margin of error at a 99% confidence level, what size of sample is needed?

Give your answer in whole people.

4. Assume that a sample is used to estimate a population mean μμ. Find the margin of error M.E. that corresponds to a sample of size 5 with a mean of 84.1 and a standard deviation of 12.7 at a confidence level of 80%.

Report ME accurate to one decimal place because the sample statistics are presented with this accuracy.
M.E. =

Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to 3 decimal places.

Answer 1

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