Central Tendency Where's the middle, what's typical in a distribution? Mode Most frequently occurring category Nominal data Median Value of the middle case when distribution is ranked Ordinal
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Section 9.1 - Comparing Population Means (a Known).
Section 9.2 Comparing Two Population Means (or
unknown) Now. We will compare population means with 0 Unknown.
Recall from Section 8.2 S
Review z- scores express a specific value from a distribution relative to the mean and standard deviation
z
X s
X
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z-score at mean will be zero A score 1 standard deviation above mean wi