QlikView Reference Manual.pdf - QlikCommunity - QlikView

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Statistical Distribution Functions
The statistical distribution functions described below are all implemented in QlikView using the Cephes
library. For references and details on algorithms used, accuracy etc, please see http://www.netlib.org/cephes/.
The Cephes function library is used by permission.
chidist (value, degrees_freedom)
returns the one-tailed probability of the chi2 distribution. The Chi2 distribution is associated with a Chi2
test. Value is the value at which you want to evaluate the distribution. Value must not be negative.
Degrees_freedom is a positive integer stating the number of degrees of freedom. Both arguments must be
numeric, else null will be returned. This function is related to the chiinv function in the following way:
If prob = chidist(value,df), then chiinv(prob, df) = value.
Example:
chidist( 8, 15 ) returns 0.9237827
chiinv (prob, degrees_freedom)
returns the inverse of the one-tailed probability of the chi2 distribution. Prob is a probability associated with
the chi2 distribution. It must be a number between 0 and 1. Degrees_freedom is an integer stating the
number of degrees of freedom. Both arguments must be numeric, else null will be returned. This function is
related to the chidist (value, degrees_freedom) (page 314) function in the following way:
If prob = chidist(value,df), then chiinv(prob, df) = value.
Example:
chiinv(0.9237827, 15 ) returns 8.0000001
normdist (value, mean, standard_dev)
returns the cumulative normal distribution for the specified mean and standard deviation. Value is the value
at which you want to evaluate the distribution. Mean is a value stating the arithmetic mean for the distribution.
Standard_dev is a positive value stating the standard deviation of the distribution. All arguments
must be numeric, else null will be returned. If mean = 0 and standard_dev = 1, the function returns the standard
normal distribution. This function is related to the norminv (prob, mean, standard_dev) (page 314) function
in the following way:
If prob = normdist(value, m, sd), then norminv(prob, m, sd) = value.
Example:
chdist( 0.5, 0, 1 ) returns 0.6914625
norminv (prob, mean, standard_dev)
returns the inverse of the normal cumulative distribution for the specified mean and standard deviation. Prob
is a probability associated with the normal distribution. It must be a number between 0 and 1. Mean is a
value stating the arithmetic mean for the distribution. Standard_dev is a positive value stating the standard
deviation of the distribution. All arguments must be numeric, else null will be returned. This function is
related to the normdist (value, mean, standard_dev) (page 314) function in the following way:
If prob = normdist(value, m, sd), then norminv(prob, m, sd) = value.
Example:
norminv( 0.6914625, 0, 1 ) returns 0.4999717
tdist (value, degrees_freedom, tails)
314