Answer:
Class width = 5
Mean = 20.375
Step-by-step explanation:
To find the class widths, find the difference between the upper and lower boundaries.
As there are gaps between the classes, the lower boundaries will be 0.5 less and the upper boundaries will be 0.5 more.
Class width = 10.5 - 5.5 = 5
To find the mean:
- find the mid-points of the classes
- multiply the mid-points by the frequency of each class
- add these
- divide by the sum of the frequencies
The easiest way to do this is to create a table (see attached).
[tex]\textsf{mean}=\dfrac{\sum fx}{\sum f}=\dfrac{815}{40}=20.375[/tex]
