Re: Unexpected Characters Appearing in Results
- To: mathgroup at smc.vnet.net
- Subject: [mg103294] Re: [mg103263] Unexpected Characters Appearing in Results
- From: Gregory Lypny <gregory.lypny at videotron.ca>
- Date: Sun, 13 Sep 2009 08:03:08 -0400 (EDT)
- References: <200909112357.TAA25403@smc.vnet.net>
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
- References:
- Unexpected Characters Appearing in Results
- From: Gregory Lypny <gregory.lypny@videotron.ca>
- Unexpected Characters Appearing in Results