The five number summary is
Min = 3
Q1 = 7 (first quartile)
Median = 15
Q3 = 19 (third quartile)
Max = 25
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Step-by-step explanation:
There are seven items listed. In the very center at slot 7/2 = 3.5 -> 4 is the value 15. The first three items (3,7,10) are below the center and the last three items (18,19,25) are above the center. Therefore, the median is 15
After figuring out the median, split the data into two sets
L = lower set = set of values below the median
U = upper set = set of values above the median
L = {3, 7, 10}
U = {18, 19, 25}
The median is not included in either set L or set U.
Find the midpoint of set L and you can see it is 7, so this is the value of Q1 which is the first quartile
Repeat the same steps for set U and the middle value is 19, so this is Q3
The min and max are simply the smallest and largest elements of the original set. Those values are 3 and 25.