Weighted Median

Hi

I need to work out the median from a set of marks with different weights. An example of how the spread sheet is laid out:

Course 1 Course 2 Course 3
20 credits 15 credits 30 credits
Mark 15 Mark 18 Mark 14

Be grateful for any help.

Thanks in advance.

No, the median of the 3 marks taking in to account the are worth different amounts. It's student course marks.

Marks are out of 22.

Can anyone help?