Answer:
Five classes
Step-by-step explanation:
1. Sort the data
You get
1.1, 1.3, 1.6, 1.7, 2, 2.6, 2.7, 2.9, 3.2, 3.2, 3.5, 3.5, 3.9, 4.6, 4.7, 4.8, 4.8, 4.9, 4.9, 5.3, 5.7, 6.4, 6.5, 7.1, 7.5, 7.6, 8.1, 8.2, 9.2, 9.4
2. Calculate the range
Range = Max - Min = 9.4 - 1.1 = 8.3
3. Calculate the class width
Divide the range by the number of classes
8.3/5 = 1.7
Round this up to 2.
4. Decide where to start the histogram
You could use classes: 1 - 3, 3 - 5, 5 - 7, 7 - 9, 9 -11
However, even numbers are easier to read.
It would be preferable to use classes: 0 - 2, 2 - 4, 4 - 6, 6 - 8, 8 - 10
5. Prepare a frequency distribution table
Note: Each class does not include its largest possible value. Thus, a value of 2 goes into Class 2 - 4, (not Class 0 - 2).