00:01
So we have data representing the age of 30 students in a statistics class, and our goal is to construct a frequency distribution that has five classes.
00:11
So the first thing i would choose to do is to put our data in order.
00:17
So the smallest piece of data here is a 14, and then there's another 14, and then we have 2 18s, and then we have 219s, we have 2 19s, we have 2 ,000, there are three twenty -one's.
01:05
There are two -22s.
01:11
There are, there's a 27, there are two -29s, there's a 30, then there are three -32s, there's a 33, then there's a 34, followed by 37, 38, 39, 39, 49, 44, 49, 51, and 52.
02:28
So in order to construct a frequency distribution, we have to determine the class width.
02:35
And to determine the class width, you take the highest piece of data minus the lowest piece of data and divide by the number of classes.
02:44
So our highest piece of data is 52 minus our lowest piece of data is 14, and we'll divide by five.
02:55
In doing so, we will get 38 over five, which is the same as seven and three -fifths, and we always round up, so we have a class width of eight.
03:09
So let's do our frequency distribution.
03:13
So we have our classes, and we'll start with our lowest piece of data, and we'll add our class width to that.
03:24
So if i add 14 plus 8, i will get the next class beginning at 22.
03:31
If i add 8 to that, i get the next class starting at 30.
03:35
Add 8 to that.
03:36
My next class starts at 38.
03:39
And add 8 to that, my final class will begin at 46.
03:44
Now, if the second class starts at 22, then the first class has to end at 21.
03:49
If the third class starts at 30, then the second class has to end at 29.
03:55
If the fourth class starts at 38, the third class was end at 37.
04:01
If the last class starts at 46, then the previous class has to end at 45.
04:10
And just like i was adding 8 over here, i can add 8 on the other side as well, which will help me determine where the final class will end.
04:23
So i'll add 8 and i will end at 53.
04:29
Next we want to determine our frequency.
04:37
So we're going to count.
04:40
So numbers between 14 and 21 would be 1.
04:44
There's 10.
04:46
There would be 11.
04:48
So we have 11 in that class.
04:52
Then numbers between 22 and 29, there are going to be five.
04:59
Numbers between 30 and 37 would be all of those, so there are seven.
05:09
Numbers between 38 and 45 would be three.
05:15
And then numbers between 46 and 53 would be the final four.
05:22
So that is your frequency distribution...