Mean: 17.3
Median: 17
Mode: 20, 15
Explanation:
Sorting the data from the lowest to highest:
9, 10, 11, 15, 15, 19, 20, 20, 24, 30
Mean = sum of all data values / the number of values
Mean = (9+10+11+15+15+19+20+20+24+30)/10 = 17.3
Median = value of the data separating the upper half of the data set from the lower half (after sorting them from the lowest to highest)
Since in this case there are 2 medians falling between 15 and 19, you have to add them and divide by 2 (similar to finding the mean of these 2 values)
Median = (15 + 19) / 2 = 17
Mode = value or values in the data set that occurs most frequently.
Mode = 15 and 20 (because they are the only ones to appear twice, whereas the other values appear only once in the data set)
