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Friday, January 20, 2012

confidence interval

confidence interval for population proportion (P) is

( p - (z)sqrt(pq/n) , p + (z)sqrt(pq/n) )

where z is the table value corresponding to the required confidence level, (two tailed)
p the sample proportion , q = 1 - p
n = sample size

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Thursday, January 19, 2012

inverse and direct variation

u is said to be directly proportional to v if u = c v for some constant c

u is said to be inversely proportional to v if u = [k / v] for some constant k

In direct variation, u increases as v increases and vice versa.

In inverse variation, u decreases as v increases and vice versa.


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Monday, January 2, 2012

problem of splitting into real and imaginary parts

if u+iv = (x +iy) ^3 , show that (u/x) + (v/y) = 4( x² -y² )

first expand (x +iy) ^3 using binomial expansion or identity and then split into real and imaginary parts then manipulate


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There is no guarantee about the data/information on this site. You use the data/information at your own risk. You use the advertisements displayed on this page at your own risk.We are not responsible for the content of external internet sites. Some of the links may not work