Find the interquartile range given these data points: 57,66,69,71,72,73,74,77,78,7879,79,81,81,82,83,83,88,89,94.
When I used the TI-84 calculator, I got ...
Q1=72.5
Q3=82.5
IQR=Q3-Q1=82.5-72.5=10
But....
When I created a stem and leaf plot I found that
Q2= (78+79)/2 =78.5
Q1=72
Q3=83
IQR= 83-72=11
So is it 10 or 11?
Did I do something wrong when using the stem and leaf plot?