Confused about Z Scores, etc.
Confused about Z Scores, etc.
I've reviewed some of the posts here and the links to the statistics sites describing Z scores but I remain confused, so pardon my revisiting this issue.
I have several scores that are shown as very substantially above the "reference." I thought the "reference" was the arithmetic mean for the CF site. Yet, I have received negative Z scores, which seem to indicate that I'm below the mean. Wassup?
I have several scores that are shown as very substantially above the "reference." I thought the "reference" was the arithmetic mean for the CF site. Yet, I have received negative Z scores, which seem to indicate that I'm below the mean. Wassup?
LeanRainmakingMachine | 2 years ago
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I think the proper way to interpret it is to say that if you z-score is -2, you are scoring 2 standard deviations below the mean. If we are talking about a test like a time test--where lower is better--that is a very good thing.
Whoopska | 2 years ago
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If your score is colored green, then it is better (than the mean); if it is red, then it is worse (than the mean). Some tests are reverse scored, but the coloration is there to make it even more... obvious.
? | 2 years ago
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e.g., on Stroop colors test, I show app. 44% above the refernce, yet have a negative 0.2 z score. That seems to mean I'm below hte mean by ).2 standard deviations, no?
and, what's the standard deviation for this sub population? 16?
Thanks for help/patience; i did not study statistics
and, what's the standard deviation for this sub population? 16?
Thanks for help/patience; i did not study statistics
LeanRainmakingMachine | 2 years ago
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Here's a calculator you can play with so that you can understand how it works: http://www.danielsoper.com/statcalc/calc22.aspx
Here's an answer that Dr. Math provided for the same question: http://mathforum.org/library/drmath/view/68384.html
You don't need to study statistics. It's really very simple mathematics.
Here's an answer that Dr. Math provided for the same question: http://mathforum.org/library/drmath/view/68384.html
You don't need to study statistics. It's really very simple mathematics.
? | 2 years ago
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I could be wrong but with reaction time based tests mental power/efficacy is inversely related to time so faster time = below the mean (-z score) but above average ability. I think...
moeman | 2 years ago
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