Im either wrong or my textbook is wrong, the former being the most likely!

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interquartile range...

I did got the lower quartile as the 3rd value and the upper as the 9th, ie 4 and 10...

so interquartile range = upper - lower...right?

so 10 - 4 = 6

im a right, text book says (9-6) = 3?