Video Transcript
The box plots below represent data
collected on the length of recorded tracks from the top 100 rap and the top 100
heavy metal music charts. On average, which genre of music
has longer tracks? And then compare the significance
of the track length 4.40 minutes for the two music genre.
Well, if we take a look at part one
first, the measure of average used in a box plot is the median, which is the
vertical bar inside the box. Well, if we read down from our
medians to the axis, we can see that the median track length for rap tracks is 4.00
minutes, whereas the median for heavy metal tracks is 4.80 minutes. And since the median for heavy
metal tracks is higher than that for rap tracks, we can conclude that heavy metal
tracks are on average longer than rap tracks.
Although it’s not part of this
question, we could however also look at the spread of the track lengths. And if we did that, we would see
that the range, which is the maximum value minus the minimum value, of rap tracks is
in fact greater. So it has a greater spread of
values. But also the IQR or interquartile
range, which is Q three minus Q one, is also greater. So we can see actually that the
differences of spread of the track lengths of rap tracks is greater than metal
tracks.
Okay, so now let’s take a look at
the second part of the question. Well, for the second part of the
question, what we want to do is concentrate on the value 4.40 minutes. So if we take a look at what this
means for rap tracks, well 4.40 minutes is where the right-hand vertical bar of the
box sits. And what this represents is the
value of Q three, our upper quartile, so the third quartile for rap. And what this means is that 75
percent of rap tracks are less than 4.40 minutes long and only 25 percent are in
fact longer than 4.40 minutes long.
However, if we look at heavy metal
tracks, 4.40 minutes represents Q one, so the lower quartile. And what this means is that 25
percent of heavy metal tracks are in fact shorter than 4.40 minutes long and 75
percent of them are longer than 4.40 minutes long. So, hence, what we can say about
the significance of 4.40 minutes is that 75 percent of rap tracks are shorter than
4.40 minutes. However, 75 percent of heavy metal
tracks are in fact longer than 4.40 minutes.
