Sunday, May 8, 2011

Confidence Interval

Determine the confidence interval for the mean, given the following information:


n=13

x̄=$220

s=56

Confidence Level= 95% Confidence

1 comment:

  1. Standard Error = s/√n = 56/√13 = 15.53
    Degrees of Freedom = n-1 = 13-1 = 12
    t-table value = 2.179

    x̄ ± t(s.e.)

    220 + (2.179)(15.53) = 220 + 33.83987 = 253.83987
    220 – (2.179)(15.53) = 220 – 33.83987 = 186.16013

    ANSWER
    Interval: 186.16-253.84

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