Mean: This is an average of all the numbers. Add up the numbers and then divide by how many numbers there are.
(3+9+4+23+6+3)/6 = 48/6 = 8
Median: The number in the middle, when the numbers are in order. If there are 2 middle numbers, average them together.
3, 3, 4, 6, 9, 23 : 4 and 6 are the middle numbers. 4+6/2 = 10/2 = 5
Mode: What value occurs most frequently? 3 is the only duplicate
Outlier: What value is abnormal to our set of data? All of our numbers are small (single digits), except for 23. That makes it an outlier.