Answer
The mean is 50.36, no mode, the median is 73, the mid range is 48.5.
Work Step by Step
The mean can be counted by summing all the data and dividing it by the number of data: $\frac{9+23+25+88+12+19+74+77+76+73+78}{11}=50.36$, the mean is 50.36. The mode is the data occurring the most times but here all data occurs one time, therefore there is no mode. The median is the average of the 1 or 2 (here 1) middle data: (73)/1=73, the median is 73. The mid range is the average of the highest and the lowest data: (9+88)/2=48.5, the mid range is 48.5. It does not make sense to calculate these because the shirt numbers do not have a numerical value.