QMB 3200 GOOD SIMPLIFIED
REVISION SUMMARY
z-score
a measure of how many standard deviations you are away from
the norm (average or mean)
Chebyshev's Theorem
At least (1-1/z^2) of the data values must be within z standard
deviations of the mean, where z > 1
if z-score more than 3
probably an outlier
IQR rule
Q1 - 1.5(IQR)
Q3 + 1.5(IQR)
left skew (neg)
right skew (positive)
covariance
A measure of linear association between two variables. Positive
values indicate a positive relationship; negative values indicate
a negative relationship
, correlation
A measure of the extent to which two factors vary together, and
thus of how well either factor predicts the other. standarized,
not influenced by units
differences between covariance and correlation
infinite numbers vs -1 to +1
unstandardized vs standardized
influenced by units vs. not
permutations
number of outcomes when n objects are to be selected from N
classical method
assigning probabilities based on the assumption of equally likely
outcomes
relative frequency method
a method of assigning probabilities that is appropriate when
data are available to estimate the proportion of the time the
experimental outcome will occur if the experiment is repeated a
large number of times
subjective method
outcomes not equally likely & data not available
complement of event a
the event containing all sample points that are not in A
REVISION SUMMARY
z-score
a measure of how many standard deviations you are away from
the norm (average or mean)
Chebyshev's Theorem
At least (1-1/z^2) of the data values must be within z standard
deviations of the mean, where z > 1
if z-score more than 3
probably an outlier
IQR rule
Q1 - 1.5(IQR)
Q3 + 1.5(IQR)
left skew (neg)
right skew (positive)
covariance
A measure of linear association between two variables. Positive
values indicate a positive relationship; negative values indicate
a negative relationship
, correlation
A measure of the extent to which two factors vary together, and
thus of how well either factor predicts the other. standarized,
not influenced by units
differences between covariance and correlation
infinite numbers vs -1 to +1
unstandardized vs standardized
influenced by units vs. not
permutations
number of outcomes when n objects are to be selected from N
classical method
assigning probabilities based on the assumption of equally likely
outcomes
relative frequency method
a method of assigning probabilities that is appropriate when
data are available to estimate the proportion of the time the
experimental outcome will occur if the experiment is repeated a
large number of times
subjective method
outcomes not equally likely & data not available
complement of event a
the event containing all sample points that are not in A
