The median from the table is

value 7, 8, 9, 10, 11, 12 ,13

frequency 2, 1, 4, 5, 6, 1, 3

median is the middle number of a set of numbers

 to find the median:

write all the numbers

7  8  9  10  11  12  13

we can see that 10 and 11 are in the middle

so add these two numbers and divide it by 2

(10+11)/2

(21)/2

10.5

1