In the given data set, all the data points except number 28 lie between 0 and 20. So, the outlier of the given data set is 28.
By arranging the data set with outlier in an increasing order, we get:
2,2,5,6,8,9,12,16,28,28,28,28
Here, 28 is repeated four times. This is the maximum number of occurrence in the data set.
∴ The modes of the data set with outlier is 28.
The given ordered data set without outlier:
2,2,5,6,8,9,12,16
Here, only number 2 repeats twice. This is the maximum number of occurrence in the data set.
∴ The mode of the data set without outlier is 2.