Answer
The mean is 6.5, modes are 4 and 4.5, the median is 6.5, the mid range is 9.5.
Work Step by Step
The mean can be counted by summing all the data and dividing it by the number of data: $\frac{6\cdot 4+6\cdot4.5+6+6+8+9+9+13+13+15}{20}=6.5$, the mean is 6.5. The mode is the data occurring the most times, which here are 4 and 4.5 both appearing 6 times. The median is the average of the 1 or 2 (here 2) middle data: (6.5+6.5)/2=6.5, the median is 6.5. The mid range is the average of the highest and the lowest data: (4+15)/2=9.5, the mid range is 9.5. It is common to finish the degree in 4 years but most of the time it takes longer.
