The data are20, 6, 42, 13, 15, 10, 9, 12, 12You can arrange the numbers from least to greatest6, 9, 10, 12, 12, 13, 15, 20, 42
The mean of this data set is 15.44
The median is 12
The mode is 12
Since the data is normally distributed, the correct measure of center is the mean.