Given data; 16, 15, 16, 16, 8, 15, 17
Arranging the given data in ascending order, we have
8, 15, 15, 16, 16, 16, 17
As per the given data, 16 is the mode of data, since it has the highest frequency, i.e. 3.
Now, if 15 is added to the given data, the mode will get changed to 15 and 16, whereas if any other number, i.e. 8, 16 or 17 is added, the mode will remain same.