Classical stem and leaf uses truncation not rounding, to make it easy to look
up values in the original data. For the wiki data
-23.678758, -12.45, -3.4, 4.43, 5.5, 5.678, 16.87, 24.7, 56.8
you can truncate to the integer part and get (here done by hand)
-2 | 3
-1 | 2
-0 | 3
+0 | 4 5 5
1 | 6
2 | 4
3 |
4 |
5 | 6
You cannot show the symmetry in i: 12, which classically would probably appear
as (again done by hand, t f s e are mnemonics for two-three four-five six-seven
eight-nine)
t | 2
-1 | 1 0
e | 9 8
s | 7 6
f | 5 4
t | 3 2
-0 | 1
+0 | 0 1
t | 2 3
f | 4 5
s | 6 7
e | 8 9
1 | 0 1
t | 2
You try to allot data zeros evenly to -0 and +0.
--Kip
Sent from my iPad
On Mar 14, 2013, at 9:40 AM, Raul Miller <[email protected]> wrote:
> I think the current wikipedia discussion of this topic is not self consistent.
>
> Earlier on the page, we see that 76 is interpreted as a stem of 7 and
> a leaf of 6, and 88 is interpreted as a stem of 8 and a leaf of 8.
>
> In the treatment of negative numbers, the stem for X is expressed as
> X/10, with non-negative integers rounded. But 76/10 rounded would be
> 8, and 88/10 rounded would be 9.
>
> If it were self consistent, I would be interested in how it treats
> numbers in the range i:12
>
> Thanks,
>
> --
> Raul
>
> On Thu, Mar 14, 2013 at 9:12 AM, km <[email protected]> wrote:
>> Negative numbers in stem and leaf plots are discussed here:
>>
>> http://en.wikipedia.org/wiki/Stem-and-leaf_display
>>
>> --Kip
>>
>> Sent from my iPad
>>
>>
>> On Mar 14, 2013, at 8:00 AM, Raul Miller <[email protected]> wrote:
>>
>>> I am not sure that negative numbers are consistent with stem and leaf plots.
>>>
>>> That said, you could use an existing mechanism by manipulating the
>>> numbers before handing them off. For example:
>>>
>>> fudge=: ] + 0&> * (_20 * 0 = 10&|) - 10 2&p.
>>>
>>> --
>>> Raul
>>>
>>> On Wed, Mar 13, 2013 at 5:16 PM, Brian Schott <[email protected]>
>>> wrote:
>>>> Raul,
>>>>
>>>> This is what I got with your newer showStemLeaf. I apologize for the
>>>> poor rendering. Suffice it to say that my experiment with your newer
>>>> showStemLeaf is unsatisfactory, too, because _2 appears in the
>>>> stemplot as 8, not 2. Perhaps you were mislead by my use of the work
>>>> stem, when leaf might have been better. I think the 0 is a stem and
>>>> the 2 4 1 and 8 are leaves. Right?
>>>>
>>>>
>>>> showStemLeaf=: (}:@":@>:@*&10@expandStems@[
>>>> ;":&>@expandLeaves)&>/@(>@{. ; <@{:)@|:@stemleaf@/:~
>>>> showStemLeaf _2 4 1 8┌─┬─────┐
>>>> │_│8 │
>>>> │ │1 4 8│
>>>> └─┴─────┘
>>>> showStemLeaf 2 4 1 8
>>>> ┌┬───────┐
>>>> ││1 2 4 8│
>>>> └┴───────┘
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> (B=) <-----my sig
>>>> Brian Schott
>>>> ----------------------------------------------------------------------
>>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>> ----------------------------------------------------------------------
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>> ----------------------------------------------------------------------
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> ----------------------------------------------------------------------
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