Explanation:
mean = sum of all data points / number of data points
(1.3+1.5+2.2+2.2+2.8)/5 = 10/5 = 2
median is the number where half of the other data points are smaller or equal, and the other half are larger or equal.
median = 2.2
mode is the data point occurring most often = 2.2
range is the difference between largest and smallest data point : 2.8 - 1.3 = 1.5