Wednesday, February 28, 2007

percentage is not always the right indicator of magnitude of change of something


when i read this news, the one thing going on in my mind since many days finally got confirmed- that percentage is not always the right way of expressing change of a quantity. example this news makes one feel that reliance has reduced the rates to a lesser extent than others, whereas the reality is that they their old rates were already lower than others, and their new rates are same as rivals. mathematically, the change expressed may be correct. but from a marketing perspective, its incorrect to say that reliance reduced their rates to a lesser extent than rivals [thus implying that their final rates are higher than rivals- because initial rates of all companies were not told in the first place]. this makes me feel that if changes are to be told in percentage form, then initial values of the quantities involved must be mentioned. otherwise the inference one can draw from those percentages [or in simpler words the mental impact on reader] may not be correct, and can convey a wrong message. if i sell just 1 copy of my software today and sell 2 tomorrow, is it right for a news story to say that i achieved 100% growth? it must mention absolute numbers too. the funny thing is that this news story does mention actual numbers [although it may be seeming that i am writing something 'against' this story]. what i am writing is about many stories -some of them in respected publications like the new york times or cnet news.com- which talk only in percentages.

that said, percentage is a good indicator in many situations. example is a company sells 1 million copies of a software per month, and sells 1.1 million in a particular month, then its good to say that there was 10% growth in sales [although merely telling 10% growth still leaves something to be desired- and again this is the intial numbers]. in this case, user's inference [or impact] will not be different from what it should be. there wont be any incorrect inferences drawn unintentionally by anyone.

basically, when reporting some change, our ultimate aim shouldn't be to just mathematically

in general, i have found percentage to be good indicator when numbers involved are large compared to magnitude of change. this looks like manifestation of real world- where 'sudden huge growth or sudden huge declines' either do not happen, or happen rarely. and generally only slow growth or decline happens, which is nicely indicated by percentages.

i think one can decide on a case-by-case basis as to what to use

Sunday, February 18, 2007

time to nitpick on gmail:-)



ok i know what i'm gonna write sounds really stupid but i observed this and so will write it. gmail homepage [this one i captured on 18-2-07 near 1 am] says 'over xyz' megabytes. now i assume that the number shown shows currently available space. in this sense, calling it 'over xyz' is incorrect, because its not over xyz megabytes, but equal to xyz megabytes at that instant of time. little mistake. anything wrong with this? (or with me...)

firefox's 'session restore' feature can be annoying or a privacy threat

this is what i discovered last year in my college's library where there was a problem with the ups system. it would keep shutting down all of a sudden, turning off all computers instantly. i was using minefield nightly builds then, and current firefox 2.0.0.1 implements session restore in same manner, so my experience applies to it. actually what i observed was that when firefox restores a user's session, it also logs you back into any email/blog etc that you were logged into before the crash. while this is certainly very good thing for personal/private computers, it caused me problem back then. why? i was usually logged into my email account, and had to wait till power was restored so that before leaving, i could ensure that i power up the computer, cause minefield/firefox to restore my session, and then log-out and clear the cache. i couldn't leave the place simply when computers would get turned off as if i didnt wait and log-out, someone else later would be taken straight to my email account by minefield/firefox. this made me feel that this feature is not suitable for public computers. imagine, a user using firefox at public terminal is logged into his email account, and by chance firefox crashes. the annoyed and pissed-off user leaves things as it is [either assuming that like in internet explorer, browser crash means one has to re-login, or 'not knowing at all about existence of some feature like session restore']. this wont do him good. this issue needs to be solved.


related official webpage
http://wiki.mozilla.org/Session_Restore

Saturday, February 17, 2007

an interesting physics/mathematics problem on distances, speeds and time (and my solution to it)

minutes back when i logged in to my gmail account, i saw a very interesting problem sent to all his orkut friends by my junior cousin. i couldn't resist the temptation to get my hands on it. since i could not find a piece of paper nearby, i opened microsoft paint and tried solving it there (very stupid thing). i hurriedly declared victory, having thought that i had solved it, and mailed the png format image to my cousin, only to be struck by a thought that made me feel my solution was incorrect. i hastily replied again to him that previous solution is incorrect. and i set out to solve it again, this time finding a piece of torn paper. i solved it, and will soon tell him the solution too. here are the resources

below is part of mail/puzzle he sent to me
this is a real brain teaser..
WARNING:the answer may seem logically correct as the figures here have been arbitarilly chosen..

ok..so there's this girl who reaches the station at 6am everyday.Her driver comes and picks her up and they reach home by 7am.
Now,one day the girl reaches the station early..at 5am and decides to walk towards her house.She meets the driver on the way and that day they reach home by 6.40 am..
The ques is..for how long was the girl walking??..and NO the answer is NOT 20 mins....
Best of luck folks!



[red][b]please inform me the ans and the way u found it[/red][/b]

and here is original incorrect solution i sent to my cousin



here is final (hopefully correct) solution
and here is the logic
  • let distance from station to home be x km
  • since driver picks up girl at six (obviously he would travel from home such that he picks her immediately) and reaches at seven, x km traveled in 1 hr. driver speed= x km/hr
  • since it takes him 1 hr from station to home, it takes him 1 hr from home to station. so he starts from home at 5 am
  • girl too started at 5 am that day. let distance [from station] at which they meet be z km
  • let girl speed be y km/hr
  • girl travels z km at y km/hr, so time = z/y hr
  • driver travels x-z km at x km/hr, so time= (x-z)/x
  • equate time by girl to time by driver to get first equation
  • since girl started at 5 and reached at 6:40, total time [girl on foot+ girl in car] = 1 hour 40 minutes. 2nd equation obtained
  • since driver started at 5 and reached home at 6:40, his journey to meeting point took half of 1 hour 40 minutes i.e. 50 minutes. his distance till meeting place = x-z and time= 50 minutes and his speed as already established is x km/hr. 3rd equation obtained. 3 variables 3 equations the problem is solved!

Tuesday, February 13, 2007

I made a high score in Rocket Mania Deluxe :-)

I am happy today, because this is just 5th or 6th time I'm playing this game. Each time I had played it previously, I was casual. This was the first time I played it with seriousness and it paid off nicely. I played a 'Strategy' type round this time at Hard level- the topmost level available in this game.

Here are some of the screenshots

This one below is when I launched 6 rockets at once...

Finally, this one shows how I build complex paths to maximize the number of simultaneous rocket fires while including all the matches present on board...

Sunday, February 11, 2007

Which game consoles would I buy If I had USD 500-600, and why not to buy a PlayStation 3

Currently, the Sony PlayStation 3 starts at about $500 for the standard version, and goes up to $600 for the premium version. Although many people are buying the $600 PS3, I believe that they could have got much more value for their 600 dollars. If I were to spend $600 on video game consoles, what I would not have done is to buy a PS3, and what I would have done is:
  • Buy a Sony PlayStation 2 for $125, plus a Nintendo Wii [$250], as well as a Sony PSP [$200], for a total of $575. With the remaining $25, I would have bought a Wii classic controller [$20]. I would have spent the remaining 5 dollars feeding myself with a burger and a coke - celebrating a wiser buy! It is not hard to observe that this deal provides significantly higher value for money [VFM] than a PS3 alone. Specifically, this deal allows one to use the huge library of now-cheap PS2 games, the fun-filled modern gaming of Wii, and the portable entertainment and gaming experiences of the PSP. This deal is also more suitable for those households which have more than one kid. However, this package lacks the ultra-advanced graphics of PS3 games.
  • An alternative deal, suitable for those who don't want to sacrifice graphics quality is - an Xbox 360 Core [X360] for $300, a Wii [$250], 2 Wii classic controllers [$40], and double the amount of burgers and coke... This package provides two next-generation game consoles, without sacrificing on graphics quality. Undoubtedly, this deal is better than the $600 PS3.
  • Yet another alternative is to go for the X360 Core [$300], the PS2 [$125] and accessories/games worth $175. Once again, this package provides more VFM than the $600 PS3.
  • Yet another alternative is to buy the standard X360 [$400], a PS2 [$125] and accessories worth $75. Again, a better buy than the $600 PS3.
PS3's VFM increases if one goes for the $500 version. It's more difficult to produce an alternative package that provides as much VFM as the $500 PS3. Some individuals may find more value in the X360 Core + PS2 + accessories [total $500] package, while others may find more value in Wii + PS2 + accessories + some games [total $500] package.

Of course, one can work out a similar alternative deal for the $400 X360 - a $250 Wii + $125 PS2 + a Wii classic controller.

The whole idea behind these alternative deals is to maximize the VFM while minimizing loss of functionality. One must also remember that these alternative deals get the owner multiple devices, providing redundancy [decreased usage of each device will increase their life; since there are multiple devices, more people can use them simultaneously].

Two things to note here:
  1. The PS2 can play DVDs, as well as games from the first generation PlayStation [PS1].
  2. The Wii can play NES, SNES, Sega Genesis, Turbo-Grafx 16, Nintendo 64 and GameCube games, in addition to Wii games. It is 7 game consoles in one body.
As a side note, it must be remembered that the PS3 can play all PS3, PS2 and PS1 games. One must carefully weigh one's gaming requirements before choosing a particular package. It must also be remembered that the PS3 includes an inbuilt Blu-ray player, which may be provide more value to select individuals.

Update (April 2009): It is now possible to buy an Xbox 360 Pro ($299) along with a PS2 ($99) for the price of one PS3 ($399 - and this PS3 does not even have backward compatibility with PS2 games). It is also possible to buy an Xbox 360 Arcade system along with a Blu-ray player for $399 total, a more sensible deal in my opinion than a PS3.

Update [Jul'16]: Following article is directly related to this idea - "Why The US Navy Should Build Smaller Aircraft Carriers".

Friday, February 09, 2007

Yes! Yes! Yes! I Cleared Number Madness :-)


I'm all smiles. Especially because this is the first time ever I played this game :-)
Although the large number - 260 - is a little worrying...

P.S. This is an extension for Mozilla Firefox, and can be download at the official AMO website

My Photography On Flickr