Back to: Chapter 10: Introduction to Estimation

5 thoughts on “Sample Size Determination (Q3) (Preview)

  1. Hi jason The formula of the sample size in the formula sheet has bracket only over the top party which is {[(z) (a/2)(SD)]^2} / B
    It is supposed to be {[(z) (a/2) (sd)] / B} ^2 right?

    1. Correct?

      1. Jh.lee26 was correct – The denominator SHOULD be within the brackets and the cheat sheet has been updated to reflect this amendment. The video shows the correct version of the formula.

  2. When retrieving the z score, its a negative. so it was -2.575. Do we ignore that?

    1. There are two z-scores used in a confidence interval. The interval occurs between z=-2.575 and z=+2.575. Whichever one you use in the formula however will give you the same result since the value of z is squared (squared negative numbers are positive).

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