Mean of a data = Sum of all observations ÷ Total number of observations
Mean of this data will be :
Sum of all observarions = 17 + 13 + 18 + 20 + 17 + 15 + 12 = 112
Total number of observations = 7
Mean = 112 ÷ 7
Mean = 16
Therefore the mean of this data set = 16
