
\sum + fractions
I take it the reason the \sum operator gives different "vertical" formats in the fractions than outside is to save space or something?
That is
$\displaystyle r = \sqrt{1  \frac{ \sum_{i = 1}^n ( y_i  yf_i )^2 }{ \sum_{i = 1}^n (y_i  \bar{y} )^2 }}$
vs
$\displaystyle \sum_{i = 1}^n$
Dan

Re: \sum + fractions
Hey Dan,
I recently learned (at MHB) to use the \limits command to force the limits of sums and products to display where I want. The code:
r = \sqrt{1  \frac{ \sum\limits_{i = 1}^n ( y_i  yf_i )^2 }{ \sum\limits_{i = 1}^n (y_i  \bar{y} )^2 }}
produces:
$\displaystyle r = \sqrt{1  \frac{ \sum\limits_{i = 1}^n ( y_i  yf_i )^2 }{ \sum\limits_{i = 1}^n (y_i  \bar{y} )^2 }}$