WEBVTT
00:00:01.120 --> 00:00:04.720
The given table shows the number of students in nine different classes.
00:00:05.080 --> 00:00:08.560
According to the table, what is the mean number of students?
00:00:09.000 --> 00:00:10.880
Round your answer to the nearest tenth.
00:00:11.680 --> 00:00:13.040
We’re looking for the mean.
00:00:13.840 --> 00:00:19.400
To find the mean, we add up all the values and then divide by the number of values there were.
00:00:20.000 --> 00:00:22.600
In this case, we have nine classes.
00:00:22.600 --> 00:00:27.880
And so, we need to add up the number of students in all nine classes and then divide by nine.
00:00:28.600 --> 00:00:39.080
That would be 22 plus 25 plus 24 plus 26 plus 23 plus 24 plus 23 plus 23 plus 27.
00:00:39.360 --> 00:00:44.040
And then, I’d double-check that there were in fact nine values.
00:00:45.200 --> 00:00:52.360
Now this process of writing down all nine values and then counting them could also be done on your calculator.
00:00:52.360 --> 00:00:55.440
You could type the nine values directly into your calculator.
00:00:56.120 --> 00:00:59.080
And whatever that’s equal to, we need to divide by nine.
00:00:59.600 --> 00:01:03.120
When we combine all nine of these values, we get 217.
00:01:03.640 --> 00:01:06.360
And we need to divide 217 by nine.
00:01:06.880 --> 00:01:10.040
When we do that, we get 24.1 repeating.
00:01:10.720 --> 00:01:18.720
Since we’re trying to round to the tenth place, we consider the digit to the right of the tenths place which is a one.
00:01:18.720 --> 00:01:20.120
And that means we’ll round down.
00:01:20.320 --> 00:01:25.440
We’ll round 24.1 repeating to 24.1.
00:01:26.400 --> 00:01:28.960
Let’s look at one more way to solve this problem.
00:01:29.480 --> 00:01:35.600
In our list, we notice that all of the classes have twenty-something students.
00:01:36.080 --> 00:01:41.560
So what we can then do is write how many more than 20 each class has.
00:01:42.240 --> 00:01:44.680
So class one has two more than 20.
00:01:45.200 --> 00:01:47.160
Class two has five more than 20.
00:01:47.960 --> 00:01:49.160
Class three has four.
00:01:49.360 --> 00:01:50.600
Class four has six.
00:01:50.600 --> 00:01:52.240
Class five has three.
00:01:52.440 --> 00:01:53.760
Class six has four.
00:01:54.120 --> 00:01:55.360
Class seven has three.
00:01:55.600 --> 00:01:57.000
Class eight has three.
00:01:57.000 --> 00:01:58.200
And class nine has seven.
00:01:58.520 --> 00:02:03.880
If we add up all nine of these values, it comes to 37.
00:02:04.320 --> 00:02:09.720
And if we divide this total by nine, we get 4.1 repeating.
00:02:10.360 --> 00:02:17.320
Well, every class has 20 and the average of the more than 20 is 4.1 repeating.
00:02:17.320 --> 00:02:25.880
And so, we combine these two values to get 24.1 repeating, which when rounded to the nearest tenth becomes 24.1.