How would I find the 5-number summary for the data set: 54, 9, 37, 15, 52, 40, 54, 78, 1, 3, 26, 26, 37?
The first thing you do is order them by value. You should do this yourself.
The lowest value gives you your MINIMUM (1)
The highest value gives the MAXIMUM (78)
The difference is the RANGE (77)
Since there are 13 values the middle one in your ordered array (the 7th) is the MEDIAN
The middle of the lower half (including the 7th) is the 4th number, which is called the FIRST QUARTILE or Q1
The middle of the higher half (including the 7th) is the 10th number,
that is called the THIRD QUARTILE or Q3
The difference between those is INTERQUARTILE DISTANCE Q3-Q1
Hope you can work it out now.