[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Statistics cu? chuo^'i



At 07:27 AM 8/3/98 -0500, you wrote:
>>Vo+'i ga^`n 50% tre^n 30 tuo^?i (gia? su+? so^' na`y chia dde^`u 50% 
>>so^'ng
>>o+? hai phi'a Nam, Ba('c vi~ tuye^'n 17 tru+o+'c na(m 75) thi` co'
i't 
>>nha^'t 
>>99,99% trong so^' 50% o+? mie^`n Ba('c va` 90% trong so^' 50% o+?
mie^`n 
>>Nam,
>>kho^ng ca?m tha^'y chu't gi` nhu.c nha~ khi kho^ng cha.y ddu+o+.c ra 
>>nu+o+'c 
>>ngoa`i. (dda^y hoa`n toa`n la` ca'c con so^' chu? quan) 
>>
>>To^?ng cu?a so^' na`y nhu+ va^.y la` : 50% + (99.99%*50% +
90%*50%)*50% 
>>~
>>97,5%.

Hello,

	Ba'c ti'nh toa'n gi` ma` hay va^.y? OK,
dde^? tui la^?m ca^?m la`m la.i ba(`ng ca'c
con so^' cu?a ba'c nhe'. Gia? su+? nhu+ ta co'
to^?ng so^' da^n la` 2000 ngu+o+`i; trong ddo'
co' 1000 tre^n 30 tuo^?i, 50% Nam va` 50% Ba('c. 
Let us tabulate them in a table as follows:

  		   South     North    Total

To^?ng so^'                            2000

N >30 yrs old        500      500      1000
Ti? le^. xa^'u ho^?  .9999    .90    
N xa^'u ho^?         500      450       950

Nhu+ va^.y thi` ty? le^. xa^'u ho^? la` 
950/2000 = 47.5%, chu+' sao la.i 97.5% ha? 
ba'c? 

	Ba'c ru't ra ddu+o+.c ba`i ho.c gi`
tu+` ca'ch ti'nh na`y chu+a?

	Nhie^`u khi ddo.c ba'o VN ma` tui
buo^`n cu+o+`i; ho. la`m nh~ con so^' tho^'ng 
ke^ chi'nh xa'c dde^'n 2 decimal places. Thu'
tha^.t vo+'i ca'c ba'c, ma^'y ca'i loa.i 
quoting numbers kie^?u na`y chi? la`m la.c
dde^` chu+' cha? informative ca'i qua'i gi`
ca?. Ta.i sao kho^ng no'i pha^n nu+?a da^n
so^' la`m X, ma` la.i no'i 49.56% la`m X.
Ba'o chi' vie^'t cho dda.i chu'ng ddo.c chu+'
co' pha?i cho scientists dda^u? Ma` ngay ca?
scientists cu~ng cha? ai care ca'i chi'nh
xa'c na`y which is itself often questionable.
Ba'c TPham no'i qua' chi' ly'!!!


==
Tuan V Nguyen
Email: rknguyen@yahoo.com


_________________________________________________________
DO YOU YAHOO!?
Get your free @yahoo.com address at http://mail.yahoo.com


The views and opinions expressed in this page are strictly those of the page author.
The contents of this page have not been reviewed or approved by the University of Minnesota.

© 1999 Minh X. Nguyen