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The
NORMDIST() function returns the
probability of a given value z occuring
by calcualting the probabilities that
make up a standard, normalized cumulative
probability distribution .
- The syntax for the function
is NORMDIST (z, mean, standard_deviation,
cumulative).
The
argument "z" must
be numerical values oherwise the function
will return the #VALUE error value. "mean"
and "standard
_deviation" can have values.....
However "cummulative"
must have a logical vlaue of TRUE or FALSE.
The "z" argument
is the value at which the NORMDIST function
evaluates the probability. It does this
by generating a normal probability
distribution using the arguments "mean",
"standard_dev" and "cumulative".
The resulting probability represents the
probability of that value occuring from
a set of randomly measured values.
[chart1]
mean = 0, standard deviation = 0.2, cumulative
= FLASE
mean = 0, standard deviation = 1.0, cumulative
= FLASE
mean = 0, standard deviation = 5.0, cumulative
= FLASE
[chart2]
mean = 0, standard deviation = 1.0, cumulative
= FLASE
mean = -3, standard deviation = 1.0, cumulative
= FLASE
mean
= +5, standard deviation = 1.0, cumulative
= FLASE
[chart3]
mean = 0, standard deviation = 1.0, cumulative
= TRUE
mean = 0, standard deviation = 2.0, cumulative
= TRUE
mean = -3, standard deviation = 1.0, cumulative
= TRUE
mean = -3, standard deviation = 2.0, cumulative
= TRUE
The normalized distribution
forms a "bell" shape, symmetrical
bout zero. The exact shape of the probability
distribution depends on the arguments "mean",
"standard" and "cumulative".The
"mean value determins the peak of the bell
shape, "standard" gives the standard deviation
or central width of the bell shape and
cumulative" determins weather the
probabilities add cumulatively to create
a cumulative distribution or a probability
density distribution (bell shape).
To learn more about the normal distribution
in statistics see: [The Normal Distribution
Mathematics Knowledgebase] and [The Gaussian
Distribution Mathematics KNowledgebase].
[The NORMSDIST function knowledgebase]
[The CHIDIST function knowledgebase]
[The FDIST function knowledgebase]
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How
to use the NORMDIST() function:
- Type " =NORMDIST( "
- Enter
the reference for the "z" data
value "A2".
- Type a comma.
- Enter
the refernce for the "mean" data
cell "B2".
- Type a comma.
- Enter
the reference for the "standard_deviation" data
cell "C2".
- Type a comma.
- Enter
the logical value for the "cunmulative
variable
"FALSE".
- Type")"
then press the "Enter" key.
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Note: Arguments
that are text that cannot be translated
into numerical values or that contain errors
will cause the function to return an error
value.
How
to use the NORMDIST() function
to create a normalized distribution
chart:
- Type " =NORMDIST( "
- Enter
the reference for the "z" data
value "A2".
- Type a comma.
- Enter
the refernce for the "mean" data
cell "B2".
- Type a comma.
- Enter
the reference for the "standard_deviation" data
cell "C2".
- Type a comma.
- Select
the cells "A3:A15".
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Note: In
earlyer versions of Excel the normdist
function was only accurate to 7 decimal
places. In Excel 2003 and newer versions
the accuracy of the normdist function
has improved to an accuracy of 14 to
15 deciamal places. |
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