A set of data items is normally distributed with a mean of 70. Convert the data item to a z-score, if the standard deviation is as given.

data item: 80; standard deviation: 15

3 answers

z = (x - mean)/ sigma

z = (80 - 70)/15

= 10/15

= 2/3 = .666666666666667 :)

If there is more, use
http://davidmlane.com/hyperstat/z_table.html
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