Find the boundaries and midpoint of each class for the distribution.?

Question

Help me find the Boundaries and midpoint from the followind data. Also, I need help finding the class width and the mean of the data.

Table:
_________________________________________________
Days Boundaries Midpoint Frequency
1 - 6 ????I?I???????I?I????I2I
7 - 12 ????I?I???????I?I????I3I
13 - 18 ????I?I???????I?I????I9I
19 - 24 ????I?I???????I?I????I6I
25 - 30 ????I?I???????I?I????I3I
31 - 36 ????I?I???????I?I????I1I
Total ?????I?I???????I?I???I24I


I think the boundaries should be the following:
.9 to 5.9
6.9 to 11.9
12.9 to 17.9
18.9 to 23.9
24.9 to 29.9
30.9 to 35.9
Total =1-36

Midpoint:
3.4
9.4
15.4
21.4
27.4
33.4
Total- 3.4-33.4

Class width: 9 - 1 divided by 6 = 1.33

Answer 1

The boundaries are 0.5, 6.5, 12.5, 18.5, etc. In general the boundary between one class and the next is the midpoint of the first one's high value and the second one's low value.

The midpoints are thus 3.5, 9.5, 15.5, etc. By defining the boundaries as above we get the same midpoints using the boundaries as we do using the given start and end values (i.e. 1-6, 7-12, etc). This is a good thing.

The class width is 6. This is the distance between boundaries. When the classes are equally spaced, it's the same as the distance between the midpoints, or between the low values, or between the high values.

Answer 2

What are the boundaries of the class 12-16