what are the different gender types of all dorms?
select distinct gender from dorm
show student capacity of the dorms with gender X.
select student_capacity from dorm where gender = 'X'
what is their average capacity?
select avg(student_capacity) from dorm where gender = 'X'
how about the total as well?
select avg(student_capacity), sum(student_capacity) from dorm where gender = 'X'