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STAT 503 Quiz I
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discrete
type of quantitative variable that can not be divided (whole # only)
Tail to the left
skewed left
If histogram is symmetric... mean and median
are similar
If histogram is asymmetric median is...
more useful than mean
5 Number summery
min
max
Q
_{1}
median
Q
_{2}
outlier
1.5*IQR +/- Q
_{1/3}
Standard Deviation
how are on average samples are from the mean
Sample Variance
Square of the Sample standard Deviation
Coefficient of Variation
gives a unitless quantity
it is sd/ȳ
hard when close to zero
need non-negative
When bell shaped:
+/- 1 SD has ___ %
+/- 2 SD has ___ %
+/- 3 SD has ___ %
68
95
99
linear transformation
linear = 1 multiplicative factor & 1 additive factor
For means
: use same formula
For SD
: additive factor is cancelled and just want absolute value of multiplicative
For Variance
: square the multiplicative
Frequency Interpretation
Interpreting probability that you would actually experiment each time
Not the only way to interpret
Probability of non-overlapping events
OR events
add P{1} + P{2}
Probablility of independent events
AND events
P{1}*P{2}
For simultaneous events visualize with...
venn diagram
For sequential events visualize with...
Probability trees
(medical tests)
AND events
sensitivity v. specificity
sensitivity- % true positives
Specificity- % True negatives
Pr(x|y)
Pr(x*y) / Pr(y)
Author
MRK
ID
258703
Card Set
STAT 503 Quiz I
Description
Stuff
Updated
2014-02-12T22:00:20Z
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