Plotting bell curve/normal distribution/Gaussian

[#1]

Hi, I havent been having any luck wih my normal distribution graph, 

When I view my chart in table format these are the values that I have for some reason there is an error calculating the values around the mean

	Frequency	Normal Frequency	Normal Frequency
-20 <= x < -15	1	0.000338372	-
-15 <= x < -10	1	0.009322085	0.028161867
-10 <= x < -5	6	-	-
-5 <= x < 0	28	-	-
0 <= x < 5	86	-	-
5 <= x < 10	29	-	-
10 <= x < 15	5	-	-
15 <= x < 20	3	-	-
20 <= x < 25	1	0.002968246	-
25 <= x < 30	1	0.000227747	0.007159788
30 <= x < 35	1	1.6E-5	0.000422699
40 <= x < 45	1	1.5E-9	2.7E-5
45 <= x < 50	1	1.4E-10	1.6E-9
-	20	-	-

The first Column is the dimension - class(salesInc,5)

2nd colomn expression - expression count(distinct salesId)

3rd column -normdist( salesInc,avg({1} total salesInc),stdev({1} total salesInc),0 )

4th comumn - (normdist( salesInc ,avg({1} total salesInc),stdev({1} total salesInc))
-normdist(above(salesInc),avg({1} total salesInc),stdev({1} total salesInc)))* Count(DISTINCTsalesId))

I got help with these formulas from a previous post

http://community.qlik.com/message/285822#285822

[swuehl]

That's probably because salesInc is ambiguous for all classes with a frequency higher than 1.

If you want a sampling point in the center of your class width, try maybe

(floor(salesInc,5)+ceil(salesInc, 5))/2

like

normdist( (floor(salesInc,5)+ceil(salesInc, 5))/2,avg({1} total salesInc),stdev({1} total salesInc),0 )

edit:

Ah, the same problem will persist using just floor() or ceil() function. Hm, maybe:

normdist( (floor(min(salesInc),5)+ceil(min(salesInc), 5))/2,avg({1} total salesInc),stdev({1} total salesInc),0 )

or

normdist( only((floor(salesInc,5)+ceil(salesInc, 5))/2),avg({1} total salesInc),stdev({1} total salesInc),0 )