24 ( Arranging in ascending order 11, 17, 19, 20, 28, 30, 39, 60, 71, 80) Since number of observations is even, the median is given by finding the average or mean of the two middle most observations So, median is (20+28) ÷ 2 = 24 (Note : In this data, there are two middle most terms 20 and 28. So, median
is the average of these observations.)