Home › AP Statistics › Statistics › The Normal Distribution › A z-score of zero corresponds to a value that is:
A z-score of zero corresponds to a value that is:
AExactly at the mean
BOne deviation above it
COne deviation below it
DAt the lowest value
Answer & Solution
Correct answer: A. Exactly at the mean
1. A z-score measures distance from the mean in standard deviations.
2. Zero distance means no departure from the mean at all.
3. The standard normal distribution is a normal distribution of standardized values called z-scores.
4. Its own mean is therefore zero and its standard deviation one.
5. Plus and minus one mark the points one deviation on either side.
_Source: OpenStax Introductory Statistics 2e (CC BY 4.0), Ch 6 'The Normal Distribution', sections 6.1-6.3_
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