How do you find how many standard deviations of a mean with a certain cost or # within a question? Any Examples?
+23247 Use a "z-score" to find the number of standard deviations a particular score has.(above or below the mean):
z-score = [ score - average ] / standard deviation
For example: if an IQ test has an average of 100 and a standard deviation of 15, then
-- if your score is 130, your z-score is [ 130 - 100 ] / 15 = 30/15 = 2 (your score is 2 standard deviation above the mean)
-- if your score is 85, your z-score is [ 85 - 100 ] / 15 = -15/15 = -1 (your score is 1 standard deviation below the mean)
-- if your score is 105, your z-score is [ 105 - 100 ] / 15 = 5/15 = 0.3333 (your score is 0.3333 standard deviations above the mean).
