daily vs weekly returns

In a previous thread ("making sense of 100's of funds") there was 
discussion of asynchony and whether it was more favourable to use daily 
vs weekly returns for analysis.

I was curious about this and although probably an agricultural approach, 
I plotted the annualized weekly vs daily standard deviations for 80 of 
the funds that happen to be available at my superannuation provider.

The plot is at http://metrak.com/tmp/exch02.png.  The dashed line is y=x.

cheers