ExcelBanter - View Single Post

James Silverton[_2_]

wrote on Thu, 13 Sep 2007
02:26:51 -0700:

rl I work for a company who deals with customer dwell time
rl between areas of a shopping centre.
rl They are tracking people between 2 points to see how long
rl they are spending in a particular area.

rl I can run reports myself, but using a Java Based program
rl that interrogates a database of customers, and where they
rl have been.

rl Anyway, the information I get is this :

rl Sample Count : 727
rl Mean Dwell Time in minutes : 9.6818
rl Standard Deviation : 22.9481

rl I also can see a standard deviation curve on the screen,
rl but I can't export this to Excel...

rl My problem is, that I already KNOW the Standard Deviation
rl and the Mean Dwell Time, but I want to re-produce these
rl curves in Excel.

If you know a mean and standard deviation, any of the several
methods for producing a normal error curve might do what you
want.....even NORMSDIST tho' it's not my favorite method.
I personally prefer

SQRT(LN(RAND())*(-2))*COS(RAND()*2*PI()) *sigma + mean

James Silverton
Potomac, Maryland

E-mail, with obvious alterations:
not.jim.silverton.at.verizon.not