Statistics

A random sample of forty-eight 200 meter swims has a mean of 3:12 minutes and a standard deviation of .09 minute. Construct a 95% confidence interval for the population mean time.

I know u: 3.12, sx: .09, n:48, c:.95

What is the formula I use to find the answer? Can anyone please leave a step by step on how to do it so I can learn and do other problems?

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1. Formula:

CI95 = mean ± 1.96(sd/√n)
...where ± 1.96 represents the 95% interval using a z-table; sd = standard deviation; n = sample size

mean = 3.12
sd = .09
n = 48

Plug the values into the formula and determine the interval.

I hope this will help get you started.

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