00:01
For part a, we're asked to find a grouped frequency distribution, and the class boundaries are given to us to start with.
00:08
So we have 12 through 18 for our first class.
00:14
Then we have 18 to 24.
00:18
And we can see that the difference between our upper and lower class is 6.
00:23
So we can keep using that class width of 6 to find our other class boundaries.
00:28
So then we would have 24 to 30.
00:34
30 to 36, so we're just adding six to the lower.
00:41
36 to 42, 42 to 48.
00:53
And the last class boundary, 48 to 54.
00:59
Now we need to figure out how many speeds are within each of these classes.
01:07
So from 12 to 18, there was one speed.
01:10
Listed that fell within that class boundary.
01:16
Now what's important to note there is that 12 is included in that interval but 18 is not.
01:21
So remember the lower boundary is included in the interval the upper boundary is not.
01:27
So including 12 up to 18 miles per hour.
01:32
From 18 to 24 there were 14 cars with speeds in between those values.
01:39
So including 18 up to 24.
01:43
From 20, from 20 to 24, from 18 to 24, there were 14 cars with speeds in between those values.
01:43
Up to 30, there were 22 cars with those speeds.
01:50
From 30 to 36, there were eight cars with those speeds.
01:56
From 36 to 42, there were five cars in that class.
02:03
And then 42 to 48 miles per hour, we had three cars...