creating a trigger to write to a different table

can i use pl/pgsql to write a trigger to update a separate table?

for example if i have a table student:
name text,
id text,
group int,
stat int,

and another table status:
stat text
group int
count int

and i update the stat in the student table, can i update the count
column in the status table to reflect the change. in the documents, i
just see triggers used on one table.

peter choe