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-   -   Standard deviation with 95% certainty, two parts. (https://www.askmehelpdesk.com/showthread.php?t=411545)

  • Oct 31, 2009, 08:57 PM
    NightWing
    Standard deviation with 95% certainty, two parts.
    By measuring the amount of time it takes a component of a product to move from one workstation to the next, an engineer has estimated that the standard deviation is 4.0 seconds.

    Answer each of the following (show all work):

    (A) How many measurements should be made in order to be 95% certain that the maximum error of estimation will not exceed 1 second?

    (B) What sample size is required for a maximum error of 2 seconds?
  • Nov 1, 2009, 06:58 AM
    galactus
    To find the sample size use the formula .

    Plug in your knowns and solve for n.

    You are given E and

    The z score that corresponds to a 95% CI is 1.

    You will get a decimal solution, so always round up your answer to the next highest integer.

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