Explain the general rationale behind using a z-score for describing how an individual performed on an exam compared to just stating the overall mean and the individual's score. How does the information differ in the two situations? What additional information are you gaining with a z-score?

Question

anonymous · Answer

What is a z-score?

ybarrap · Answer

The z-score normalizes random variables to have a mean of zero and a standard deviation of 1. This allows you to directly compare any random numbers regardless of range. It then represents whether the random variable is above or below the mean and if it it way beyond central tendency given by the z-score, which indicates the number of standard deviations from 0.

andijo76 · Answer

z score is used in statistics @TeslaMotors

ybarrap · Answer

If you compare to overall mean rather than z-score, you can compare within that particular set of random values. However, if you wanted to compare to other sets of random variables, using the z-score would be more informative because then you can see how a particular SET of random numbers compares to each other sets rather than just how an individual number compares to numbers WITHIN the set.

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