Solution:
The 5-number summary consists of the minimum, the Q1, the median, the Q3, and the maximum, respectively.
We can easily determine the minimum and the maximum because the data is already arranged.
Minimum = 2.0
Maximum = 9.0
Now, for the median, there are 20 data that are given. The middle of 20 is an even number so we will average the 10th and the 11th to get the median.
Median = (4.0+4.0)/2 = 4.0
For Q1, we will find the middle of the lower half. Since the middle is even, we will average the 4th and the 5th.
Q1 = (3.5+3.5)/2 = 3.5
For Q3, we will find the middle of the upper half. Since the middle is even, we will average the 4th and the 5th.
Q3 = (5.5+5.5)/2 = 5.5
ANSWER:
The 5-number summary: 2.0, 3.5, 4.0, 5.5, 9.0