Calculating the Mean PE & Standard Deviation for ETFs

hello victor,
you have demonstrated many examples of how the Average PE and Standard Deviation (SD) can be plotted for individual companies.
i am currently able to obtain the graphs for the Average PE for ETFs such as the SPY and QQQ.
however, may i know:

1. if the SD can also be plotted for the SPY and QQQ as well?
2. the reason of me asking is that i have access to a Bloomberg terminal but it appears that i am unable to plot their SD  (even after making calls to the Bloomberg helpdesk).
3. if the Standard Deviation for SPY and QQQ cannot be plotted out, may i know why?

Thanks in advance for your help.
Edmund