I am trying to make a histograph. The tutorials are not helpful enough.?

Question

the speeds of 40 cars clocked by radar on a particular road in a 35-mph zone on a particular afternoon:
30, 36, 42, 36, 30, 52, 36, 34, 36, 33, 30, 32, 35, 32, 37, 34, 36, 31, 35,
20, 24, 46, 23, 31, 32, 45, 34, 37, 28, 40, 34, 38, 40, 52, 31, 33, 15, 27,
36, 40.
The can't histograph I made did not look right.

The graph part is confusing to me

Answer 1

Here's a histograph with intervals of 1:
15 *
16
17
18
19
20 *
21
22
23 *
24 *
25
26
27 *
28 *
29
30 ***
31 ***
32 ***
33 **
34 ****
35 **
36 ******
37 **
38 *
39
40 ***
41
42 *
43
44
45 *
46 *
47
48
49
50
51
52 **

Or you can do it with a different interval (e.g. 5):
15 - 19 *
20 - 24 ***
25 - 29 *
30 - 34 **************
35 - 39 ***********
40 - 44 **
45 - 49 **
50 - 54 **

For a graph of the data, look at the attached image: