this is a novice question.... I can't get excel to figure out the
descriptive statistics for a simple survey. it goes like this.

The ages of newly hired, unskilled employees were grouped into the following
distribution:
18 to 21 4
21 to 24 8
24 to 27 11
27 to 30 20
30 to 33 7
I just want to figure out the median age! Help me please!!