### Estimating the sample size based on normal distribution

Assignment Help Basic Statistics
##### Reference no: EM1313514

Problem # 1:

A random sample of 81 weeks showed Hootch Springs Water Company to have an average weekly sales level of \$8500 with a sample standard deviation of \$810. Construct the 90% and 95% interval estimates for the population mean weekly sales.

Problem # 2:

Karefree State University has an enrollment of 18,000. Researchers took a sample of 900 and found 477 students wanted a Field Hockey team. Construct the 95% and 99% Interval estimates for the population proportion.

Consider the two previous problems. At 95% confidence what sample sizes would you need:

A. to reduce the margin of error in problem #1 to 100?

B. to reduce the margin of error in problem #2 to .025?

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