Solution:

We arrange given data in ascending order 6, 6, 7, 8, 10, 10, 10, 11, 13

Mean = Ʃx_i/n

= (6+6+7+8+10+10+10+11+13)/9

= 81/9

= 9

Hence the mean is 9.

Here number of observations, n = 9 which is odd.

Median = ((n+1)/2)^th term

= (9+1)/2

= 10/2

= 5^th term

= 10

Hence the median is 10.

In the given set, 10 occurs maximum number of times.

Hence the mode is 10.