What is the exactly calculation of the fractile function?

[#1]

Hi everybody! I am crazy with the calculation of the fractile function.

I have this table:

vendedor:

LOAD * INLINE [

vendedor, venta

1, 77

2, 79

3, 90

4, 85

5, 66

6, 100

7,88

8,97

9,100

10,87

11,90

12,92

];

when I do in object text the calculation: =fractile( total venta , 0.3) return the value: 85.6

BUT... what is the exactly calculation of the fractile function?

Because I am not statistical so I had to learn how function the fractile function and in this video:  https://www.youtube.com/watch?v=PDzLETjOlL0

the result is 84.4, different of 85.6 (value returned by Qlikview)

who is wrong? what happens?

Thank you in advance !!!

[MK_QSL]

Fractile() mystery revealed

What exactly a Fractile function does?

[sunny_talwar]

In a text box object, it won't matter if you use TOTAL or not, it would give the same number. But Fractile(venta, 0.3) is the 30th percentile of the data within venta. Where does this 84.4 numbers come from?

[sunny_talwar]

Manish what is the mystery here? Not sure I understand the issue. Can you elaborate the finding from those two links?

[MK_QSL]

Fractile works for values by Ascending order..

vendedor	venta
5	66
1	77
2	79
4	85
10	87
7	88
3	90
11	90
12	92
8	97
6	100
9	100

=fractile( total venta , 0.3)

1) You have total 12 Values so 12 * 0.3 = 3.6

So we need at least 3 values from result...

In fractile we need to add one in this... 3.6 + 1 = 4.6

So we need

=4th Value + (Difference Between 5th and 4th Value)*30% share

=85 + (87-85)*30%

=85 + 0.6

=85.6

[#6]

Hi Sunny T, in this video explains how works the fractile function with the same example that I use

STAT 344 &350 Fractile vs Johnson's Method for calculating Percentiles Quartiles.mp4 - YouTube

[MK_QSL]

Difference is Percentile works like (12+1)*30% = 3.9

=3rd Value + 0.9(4th - 3rd value)

=79 + 0.9*(85-79)

=79 + 5.4

=84.4

[#8]

Hi Manish, your result it's okay.. BUT! try this.. I can't end to understand..

I want to know the porcentage of 70%

Therefore in QV  I do =fractile( total venta , 0.7) = 91.4

But if I do the calculation the result is different.

I do:

12 x 0.7 =8.4

8.4 + 1 = 9.4 I use the 9th value

9th + (10th - 9th) x porcent

92 + (97 - 92 ) * 0.7 = 95.5

And 95.5 is different to 91.4 (QV result)

The same happens when I do the calculation with 0.25%.

Thanks for your help, I am really confuse with this issue.

[MK_QSL]

I will work on this and come back to you soon.

[#10]

Ok, thank you so much!

I note different behaviors between porcentage with one or two decimals. for example the calculation for 0.4 is different of 0.45, because when I do the calculation of 0.4 the result is the same that QV shows me, but when I do the same calculation with 0.45 the result that QV gives me is different that I have it.

Other thing that I noted is the position of the elements that I must to take when the porcentage are less of 0.5 or more of 0.5

Fuck!

And other issue that I noted is that I took the same values of the document: 'What exatly a fractile function does? with the same porcentages: 0.25 ; 0.5 and 0.75 and the values that QV shows me are different of the results showed in the document, so crazy!