The given number of cookies are
11, 10, 24, 8, 20, 24, 30, 12, 23
At first, we should arrange them ascendingly (from small to big)
8, 10, 11, 12, 20, 23, 24, 24, 30
Now, we have to find the median (IQ2)
The median is the middle term of the data
Since there are 9 numbers, then the median is the 5th one
The 5th number is 20, then
The median is 20
IQ2 = 20
Now, we need to find the 1st and 3rd interquartile
The 1st interquartile is the median of the first 4 terms, then
[tex]IQ1=\frac{10+11}{2}=10.5[/tex]The 3rd interquartile is the median of the last 4 numbers, then
[tex]IQ3=\frac{24+24}{2}=24[/tex]Now, we can draw the box-and-whisker