[BlindMath] Reading an ascii math formula in nvda

Sat Nov 20 06:49:38 UTC 2021

Hello,

It is a slight change on a standard deviation formula.

In a standard deviation, the individual observations are compared to a constant mean. Your formula has a mean that is changing each day. In both situations, deviations get squared, then added up, divided by one less than the number of observations (sample not population) giving a variance type thing that then gets square root applied to get back to the original scale.

You end up with a single summary statistic that relates to the deviations from target. In your case, the target is shifting but the daily deviations should be very small if the portfolio is perfectly tracking the benchmark.

I think the authors could easily have simplified the presentation by using something like X and B for the two series, both subscripted with t for time, but we seldom get to correct any author's work other than our own.

Glad my stale finance degree can be put to better use than managing my mortgage payments.

Jonathan

-----Original Message-----
From: BlindMath <blindmath-bounces at nfbnet.org> On Behalf Of Pranav Lal via BlindMath
Sent: Saturday, 20 November 2021 7:19 PM
To: 'Blind Math list for those interested in mathematics' <blindmath at nfbnet.org>
Cc: pranav.lal at gmail.com
Subject: Re: [BlindMath] Reading an ascii math formula in nvda

Dear Jonathan,

Many thanks and yes, I am comparing tracking error of exchange traded funds.
So, is this  just a covariance computation? 

Pranav

-----Original Message-----
From: BlindMath <blindmath-bounces at nfbnet.org> On Behalf Of Jonathan Godfrey via BlindMath
Sent: Saturday, November 20, 2021 8:03 AM
To: Blind Math list for those interested in mathematics <blindmath at nfbnet.org>
Cc: Jonathan Godfrey <A.J.Godfrey at massey.ac.nz>
Subject: Re: [BlindMath] Reading an ascii math formula in nvda

Looks like the Euclidean distance between two series. Given it is finance, I suspect returns series of two asset classes, or perhaps one asset compared to an index of some description.
It is being adjusted for the lengths of the series.

The square root puts it back on the original scale; without the square root, I'd call it a covariance.

HTH
Jonathan

-----Original Message-----
From: BlindMath <blindmath-bounces at nfbnet.org> On Behalf Of Neil Soiffer via BlindMath
Sent: Saturday, 20 November 2021 2:47 PM
To: Blind Math list for those interested in mathematics <blindmath at nfbnet.org>
Cc: Neil Soiffer <soiffer at alum.mit.edu>
Subject: Re: [BlindMath] Reading an ascii math formula in nvda

In a new browser tab, open
https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmathjax.gi%2F&data=04%7C01%7Ca.j.godfrey%40massey.ac.nz%7C5633b7d6f3f34fe8842008d9abeddfec%7C388728e1bbd0437898dcf8682e644300%7C1%7C0%7C637729860440202397%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=BbTMUNQCmb0CbGEIJPDTSVj8QIjMYXF5W6L0FdS%2Fuxo%3D&reserved=0
thub.io%2FMathJax-demos-web%2Finput-tex2chtml.html&data=04%7C01%7Ca.j.go
dfrey%40massey.ac.nz%7Cbeda1318cb0846ba6ac208d9abc7ccef%7C388728e1bbd0437898
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4yw7s43zYPoEPvRIvpvBtaX07VytKD470ec%2Bacgl2eE%3D&reserved=0.
This is a MathJaX demo page where you can paste in TeX and get the result displayed with MathML accessible to AT.
Select the example text in the edit area and replace it with your expression (which is TeX).
Click "Render TeX"
Move to the focus to the area below and you should be able to hear it and interact with it. I only tried MathPlayer, but the same is probably true for acess8math.

Hope this help,

Neil Soiffer

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<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Fri, Nov 19, 2021 at 4:43 PM Pranav Lal via BlindMath < blindmath at nfbnet.org> wrote:

> Hi all,
>
> I need to read the following formula written in ascii math with nvda. 
> I see that math player is not an option. I am not as familiar as I 
> should be with ascii math notation.
> E_d = \sqrt{\frac{\sum_{t=1}^{N}(R_{b,t} - R_{x,t})}{N-1}}
>
>
> For instance, what does \sum_{t=1}  mean? What is being added?
>
> I am using the add-on called access8Math.
>
> I went to
> https://apc01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fascii
> math.org%2F&data=04%7C01%7Ca.j.godfrey%40massey.ac.nz%7Cbeda1318cb
>
0846ba6ac208d9abc7ccef%7C388728e1bbd0437898dcf8682e644300%7C1%7C0%7C63772969
6919301735%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBT
iI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=xtUxksyEcTwiC4EzMaxs6EpxpNMJexHY2
cY1V%2FxIzP8%3D&reserved=0  and rendered the above formula. The math content is being displayed but I am unable to navigate amongst different parts of the expression. NVDA is reading  the entire expression as a block of text.
>
> It may be easier for me to just read the above formula as is, so could 
> someone translate it into plain English perhaps?
>
> Note:
> I am doing a course relating to finance which is where the above 
> formula is being used.  The people have not had a blind student before 
> and are happy to help in whatever way they scan.
>
> I am using NVDA version 2021.2.
> Firefox version = 94.0.1 (64-bit)
> Windows version = 21H2 (OS Build 22000.318)
>
> I tried the formula in google chrome. I can hear the rendering too but 
> it sounds different than it does in firefox. Hitting enter on the 
> clickable expression does nothing and I cannot interact with the 
> expression in parts to understand it.
> Google chrome Version 96.0.4664.45 (Official Build) (64-bit) Pranav
>
>
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