How do you find the range and interquartile range of a data set?
Get the range by subtracting the lowest value from the highest value
I'm not familiar with interquartile range, but here is a guess.
Arrange your data from highest to lowest, or vice versa.
Group your sorted data into 4 groups with equal number of elements (as much as possible). Subtract the lowest value in the group from the highest value in the group. Do this for each group and you probably have your interquartile range.
Note that if you do this, you are not assured of equal range per quartile.
Another guess with the quartile range, just divide the actual range by 4.
Note that if you do this, you are not assured that each quartile will have the same number of elements.