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Re: Unexpected Characters Appearing in Results

  • To: mathgroup at smc.vnet.net
  • Subject: [mg103295] Re: [mg103263] Unexpected Characters Appearing in Results
  • From: DrMajorBob <btreat1 at austin.rr.com>
  • Date: Sun, 13 Sep 2009 08:03:21 -0400 (EDT)
  • References: <200909112357.TAA25403@smc.vnet.net>
  • Reply-to: drmajorbob at yahoo.com

I upgraded to Snow Leopard, too, and there's no problem here. (Not with  
Mathematica so far, that is.)

Bobby

On Sat, 12 Sep 2009 18:57:41 -0500, Gregory Lypny  
<gregory.lypny at videotron.ca> wrote:

> Thanks for checking, Bobby.  Yes, I executed exactly what you did  
> below.  I was thinking that it might have to do with upgrading to Snow  
> Leopard the other day.  I've got a message in to Wolfram tech support.   
> See what they have to say.
>
> Regards,
>
> 	Gregory
>
>
> On 2009-09-12, at 5:21 PM, DrMajorBob wrote:
>
>> Here's what I get at my machine (64-bit Mac OS X, Mathematica 7.0):
>>
>> p = {{107, 138}, {119, 129}, {104, 101}, {107, 91}, {123, 94}};
>> stdDev[x_] := Sqrt[Plus @@ (Plus[#, -Mean@x]^2 & /@ x)/Length@x]
>>
>> stdDev@p // N
>>
>> {7.53658, 19.1896}
>>
>> r = Differences@p/Most@p
>>
>> {{12/107, -(3/46)}, {-(15/119), -(28/129)}, {3/104, -(10/101)}, {16/
>>  107, 3/91}}
>>
>> stdDev@r // N
>>
>> {0.105942, 0.0893377}
>>
>> I don't know why you're getting those "/.10" artifacts, but I don't  
>> know if that's exactly what you did, either.
>>
>> Bobby
>>
>> On Sat, 12 Sep 2009 15:30:13 -0500, Gregory Lypny  
>> <gregory.lypny at videotron.ca> wrote:
>>
>>> Hi Bobby,
>>>
>>> Yeh, you're right.  Kind of skimped on the details.  Sorry about that.
>>>
>>> Here's some data, five observations each on the prices of two stocks.   
>>> First element in each is stock 1 and the second element is stock 2.
>>>
>>> p= {{107, 138}, {119, 129}, {104, 101}, {107, 91}, {123, 94}}
>>>
>>> Here's a function for computing standard deviation that goes down each  
>>> "column" as it were.  I think a version of this was suggested on  
>>> MathGroup.
>>>
>>> stdDev[x_] := Sqrt[Plus @@ (Plus[#, -Mean@x]^2 & /@ x)/Length@x]
>>>
>>> The standard deviation of price is not a problem.
>>>
>>> {7.53658, 19.1896}
>>>
>>> Now I convert the prices to returns,
>>>
>>> (r = Differences@p/Most@p)
>>>
>>> {{12/107, -(3/46)}, {-(15/119), -(28/129)}, {3/104, -(10/101)},  
>>> {16/107, 3/91}}
>>>
>>> leaving me with four observations each because of the differencing.   
>>> Taking the standard deviation of returns gives me
>>>
>>> {0.105942 \.10, 0.0893377 \.10}
>>>
>>> where the \.10 appears when I copy from Mathematica and paste into my  
>>> mail software, but in Mathematica, the \.10 appears as an exclamation  
>>> mark (!) with what appears to be a skinny space between it and the  
>>> last digit reported for each result.
>>>
>>> The answers for returns are correct, and the exclamation mark still  
>>> appears if I compute r as a numerical approximation rather than  
>>> rationals.  Any thoughts?
>>>
>>> Regards,
>>>
>>> 	Gregory
>>>
>>>
>>>
>>> On 2009-09-12, at 1:47 AM, DrMajorBob wrote:
>>>
>>>> Details, Gregory. Details.
>>>>
>>>> Bobby
>>>>
>>>> On Fri, 11 Sep 2009 18:57:30 -0500, Gregory Lypny  
>>>> <gregory.lypny at videotron.ca> wrote:
>>>>
>>>>> Hello everyone,
>>>>>
>>>>> I created a function to compute standard deviation, and in some
>>>>> instances it returns a result with an exclamation mark (!) at the  
>>>>> end,
>>>>> as in
>>>>>
>>>>> 	0.143855 !
>>>>>
>>>>> When the result is copied as plain text and pasted elsewhere, it  
>>>>> comes
>>>>> out as
>>>>>
>>>>> 	0.143855 \.10
>>>>>
>>>>> Any reason why this is happening?  I recently upgraded my Mac to Snow
>>>>> Leopard, and thought that might be the cause.
>>>>>
>>>>> Regards,
>>>>>
>>>>> 	Gregory
>>>>>
>>>>
>>>>
>>>> --DrMajorBob at yahoo.com
>>>
>>
>>
>> --DrMajorBob at yahoo.com
>


-- 
DrMajorBob at yahoo.com


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