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Math Help - Estimation from Sample Data:

  1. #1
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    Estimation from Sample Data:

    A sample random sample of 30 has been collected from a population for which it is known that σ= 17.0. The sample mean has been calculated as
    342.0, and the sample standard deviation is s=14.9. Need some help to construct and interpret the 95% and the 99% confidence intervals for the population mean.
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  2. #2
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    Quote Originally Posted by loriemomof2 View Post
    A sample random sample of 30 has been collected from a population for which it is known that σ= 17.0. The sample mean has been calculated as
    342.0, and the sample standard deviation is s=14.9. Need some help to construct and interpret the 95% and the 99% confidence intervals for the population mean.
    The sample mean is normally distributed with mean equal to the population mean \mu and sd s=\sigma/\sqrt{N} where N is the sample size.

    So the required confidence intervals should be:

    [m-z_{p}s,\ m+z_{p}s]

    where z_p is the critical value for a standard normal distribution so that p(|z|<z_p)=p which you look up in a table. But you should have memorised that z_{0.95}=1.96 because it occurs so often.

    .
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