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-   -   The formula for NORMSDIST is wrong? (https://www.excelbanter.com/excel-worksheet-functions/89454-formula-normsdist-wrong.html)

SyBorg

The formula for NORMSDIST is wrong?
 
nI tried using the equation from the help menu to verify NORMSDIST(1.3333),
as follows:

(EXP(-POWER(1.3333,2)/2))/SQRT(2*PI())

but I don't get the same answer. Instead, I get 0.164017.

What am I doing wrong?

Bernard Liengme

The formula for NORMSDIST is wrong?
 
normSdist always returns the cumulative value (ie the area under the curve
up to value of z)
normdist lets you choose cumulative or not.
Also the first is set for mean = 0, stdev=1 while the second allows you to
specify these values.
The formula =NORMDIST(1.3333,0,1,0) returns 0.164017 since the last argument
of 0 specifies non-cumulative.
best wishes
--
Bernard V Liengme
www.stfx.ca/people/bliengme
remove caps from email

"SyBorg" wrote in message
...
nI tried using the equation from the help menu to verify
NORMSDIST(1.3333),
as follows:

(EXP(-POWER(1.3333,2)/2))/SQRT(2*PI())

but I don't get the same answer. Instead, I get 0.164017.

What am I doing wrong?




David Biddulph

The formula for NORMSDIST is wrong?
 
"SyBorg" wrote in message
...
nI tried using the equation from the help menu to verify
NORMSDIST(1.3333),
as follows:

(EXP(-POWER(1.3333,2)/2))/SQRT(2*PI())

but I don't get the same answer. Instead, I get 0.164017.

What am I doing wrong?


Doesn't the help say that NORMSDIST is the *cumulative* function, whereas
the (EXP(-POWER(z,2)/2))/SQRT(2*PI()) is the *density* function?
Plot each against z.
Integrate the density from z = - infinity and compare that with the
cumulative.
--
David Biddulph




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