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Homework Help: Probability and statistics ques

  1. Jun 22, 2008 #1
    QUES: the yield of a chemical process is bieng studied. the past 5 days of plant operation have resulted in :91.6, 88.75, 90.08, 89.95, 91.3. Find a 95% two-sided confiendce interval. Thanks folks
  2. jcsd
  3. Jun 22, 2008 #2
    I don't know the answer.

    But, you need to show some of your effort before anyone else gonna help you.
  4. Jun 22, 2008 #3
    i tried using the eqautaion "Confiendnce interval on the mean, varaiance known" but i am not sure how to get the variance. thanks
  5. Jun 23, 2008 #4
    Let [tex] \bar{x}[/tex] be the sample mean, what is [tex] \bar{x}[/tex]?
    What is n, the sample size?
    What is s, the sample standard deviation?
    What distribution should you use(based on n)? Then find the 95% confidence interval.
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