**Unformatted text preview: **3. 4: Measures of positions and outliers.
Determine and interpret
2 - scores .
2 - score: represents the distance that a data
value is from the mean in terms of the
number of standard deviations .
population z- score
Sample z - score
Z - X - M
2 =
X - X
is
If a data value is larger than the mean the
2- score is positive; If its smaller , the z-score
is negative. E-scores measure the # of
standard deviations an observation is above
or below the mean .
interpret Percentiles
*th
percentile : denoted Pr of a set of data is
value such that k percent of the observations
are less than or equal to the value .
Determine and interpret
Quartiles
smallest
Quartile: divide data sets into forths
data
median
Value .
jargest
1 25 Q
Data
7 8
254 Q2 25%% Q3 25#%
value....

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- Fall '08
- Staff