Answer
The mean is 1.889, mode: -2, the median is 1.5, the midrange is 8.
Work Step by Step
The mean can be counted by summing all the data and dividing it by the number of data: $\frac{11+3+0-2+3-2-2+5-2+7+2+4+1+8+1+0-5+2}{18}=1.889$, the mean is 1.889. The mode is the data occuring the most times, which here is -2 appearing 4 times. The median is the average of the 1 or 2 (here 2) middle data: (2+1)/2=1.5, the median is 630.5. The midrange is the average of the highest and the lowest data: (11+5)/2=8, the midrange is 8. These falues do not support the legend, because all of them are a lot lower than 6.8.