Understanding report data: graphs, summaries

I’ve set up weekly and mail reports, and am very pleased with what I get - but being an analytics noob I have a hard time understanding the meaning of some of it…

q1: I suppose that all numbers shown are the aggregate (totals or averages) for the whole week correct? e.g. unique visitors (sum), actions per visit (avg)

q2: graphs showing data evolution over time (eg. pageviews):
a) is every data point on that graph corresponding to the aggregate of 1 week?
b) in between each pair of vertical grays lines, are there supposed to be 5 data points? Can a dot be displayed for each?
c) if so, why is a vertical line painted every 6 weeks? Is it a fixed interval or calculated dynamically?
d) would it be possible to find a better graphical representation of the fact that each vertical line corresponds to a 1-week period?
In short: I find those graphs a bit hard to read

q3: the graphs used in monthly reports could proably also benefit of displaying a dot for each data point

Thanks
Gaetano