The best measure of center tendency for this set of data would be the median. It is the best measurement because the data set has an outlier. The outlier is the 30. So to find the median we first order the data set and then find out if the set is an even or odd set. This set is even so we just chose the middle number. If the set was even, we would add the two center number and divide them by 2.
3, 3, 4, 4, 4, 5, 5, 5, 30
The center tendency = 4
That would a set of 5 numbers in ascending order with 4 being the middle one and the other 4 being the highest possible So it is
2, 3, 4, 9, 10
Mean is 28/5 = 5.6 answer
( I am assuming that each number is different)
Of duplicates is allowed then its 4 4 4 10 10 whose mean is 6.4