Hello Guys

I have a dataset which shows the following:
Firm date return DayofWeek
AARGKB January 3, 2008 -0.001 4
AARGKB January 4, 2008 -0.007 5
AARGKB January 7, 2008 -0.013 1
AARGKB January 8, 2008 -0.0121 2
.....
I have a dataset with over 200 different firms. Now i want to have this result:
DayofWeek Mean St. Dev N t-value
1
2
3
4
5
So im trying to collapse the mean of every monday in one, the mean of every tuesday in one and this for every day of the week.
Code:
collapse (mean) adjretadd1, by(dayofweek)
With this code i managed to get the mean, which i think is correct. But when i now try to get the other ones (StDev, N and t-value), i don't know how i can do it with one command.
Code:
correlate dailyreturns, means cov
With this, i get then the mean of the 5 days in one, but that's not what i wanted. I also get only N of 5, which is also not correct (the problem is that i then take the results i get from my first command and calculate with them, but i want to calculate with the initial dataset). Is there a command with which i get the results i wanted at once?

Thank you very much for every help.

Best,
Anthony