3a. Data Set A has more numbers between the range 20-30 so we can say that it is skewed to the right (the tail is on the right side and majority of the data set is on the left). For Data Set B, we can see that most of the numbers lie in the center so it would more or less be normally distributed.
3b. The best measure of center for Data Set A is the median since it is skewed and therefore the value of the mean would be influenced by the extremes. For Data Set B, the mean will do just fine since it is normally distributed.
3c. The interquartile range would be better for Data Set A since the IQR is not affected by outliers and Data Set A has an extreme value (55) while the standard deviation would do just fine for Data Set B since the data is normally distributed therefore the standard deviation could be properly interpreted.