00:03
Hello and welcome back to statistics.
00:05
Today we have a data problem, so let's get right into it.
00:08
So it tells us that in tobacco and alcohol use in g -rated children's animated films by goldstein, sobel, and newman, the lengths and seconds of scenes showing tobacco use and alcohol use were recorded for animated children's movies.
00:25
And the problem tells us to refer to elementary statistics 13th edition dataset 11, alcohol and tobacco in movies, which is this data set that you can see here in my spreadsheet.
00:36
And we need to find the mean and median for tobacco times.
00:39
And next, we also need to find the mean and median for alcohol times.
00:44
And then we finally have to determine whether there is a difference between those times and which appears to have a larger problem, seen showing tobacco use or seen showing alcohol use.
00:58
Because, of course, both aren't really ideal for children's movies.
01:03
So to the left you can see the list of movies and the company that made them.
01:08
And the length of the movie, the tobacco use length in seconds and the alcohol use length in seconds as well.
01:15
And so that's all 50 of the data sets.
01:19
And so i've already done, i've reorganized it in terms from the minimum length of tobacco use seconds to the highest.
01:29
So zero to 500, 48 seconds and 0 to 414 seconds.
01:35
So to start us off, let's find the sum of the tobacco use because as we know to find the mean of tobacco use, it's going to be the sum of all the data set divided by the number of pieces of data.
01:51
So we know that n or the number of data pieces is 50.
01:57
So now we just need to find the total sum of the data.
02:00
So to do that, i'm just using google sheets.
02:02
So we can use a simple function, the sum function.
02:06
So the sum of all these, or you can do this by hands, but i'm just using google sheets just for the ease of it.
02:16
So the sum of it is 2 ,872 seconds.
02:19
And to find the mean for tobacco use, we can just make it equal to that sum and divide it by 50 because there are 50 data cases.
02:30
Well, there's 50 movies that we're comparing.
02:34
So the mean tobacco use is going to be 57 .44.
02:38
Now, we need to find the median.
02:40
And the median is different in that it's not the average.
02:45
It's not the mean, but it is the halfway point in terms of the data set.
02:52
Now, the median is more useful for when a data set is skewed or not symmetrical, which as you can see here in this data set, it's pretty skewed because there's almost half the values are zeros and then you get up to really high values and it's not really consistent.
03:16
So let's just count.
03:18
So half of 50 is 25.
03:20
So we need to find the 25th value of tobacco use.
03:25
So this is the first, second, third, fourth.
03:29
Here, i'll do it like this.
03:31
One, two, third, fourth, fifth, sixth, seventh, eighth, eighth, ninth, tenth.
03:37
10th, and here is the 25th highest data.
03:53
So this is the midpoint between all 50 data sets for tobacco use.
03:57
So we know that the median for tobacco use is just five seconds.
04:00
So that's a lot different than the mean because this data set is indeed skewed because almost half the data is zero for tobacco use.
04:10
So the majority of the movies have like zero seconds of tobacco use, rather.
04:19
And so of course, the average is going to be so high because we have values like 548.
04:25
Now let's see what movie that came from.
04:27
That came from the three cabbieroes.
04:30
So that had a lot of tobacco use...