This one will require you to note how many values are in each bar/section of the histogram. So, first recognize the question tells us the total number is 691. Meaning n=691. Also notice that the problems specifies each bar is inclusive of the left side value, but not the right. Next, we need to approximate the number of values in each bar. This will differ slightly from person to person, but should be relatively close. My approximations are: Ages 11-12 about 47 Ages 12-13 about 74 Ages 13-14 about 160 Ages 14-15 about 145 Ages 15-16 about 150 Ages 16-17 about 98 Ages 17-18 about 17 From here, we have to calculate the location of each quartile. So, Q1 is located at (691+1)/4= 173, so position 173. From here, we determine where that position is. Ages 11-12 account for 47 positions, its not in there. Ages 11-13 (add 11-12 bar with 12-13 bar) account for 47+74=141 position, its not in there. The 13-14 bar accounts for 160 positions, so we know that Q1 must be located somewhere in there. Since it does not include the right hand value of the bar, this tells us Q1 is 13. You will follow