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There's more than one way to talk about the 'middle' of a dataset. In this video we'll look at mean, median, and mode and see when you might want to use each one!
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Now that we've got some bounds for
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our data, it would be nice
to know where the middle is.
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Unfortunately, there is a few
different ways to define the middle.
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Let's look at three of them.
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The first and most common way to
look at the middle of a data set
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is to use the mean,
also known as the average.
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To find the average of a set,
add up all the values and
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then divide by how many values there are.
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One problem with averages is that
they're easily influenced by outliers.
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If we're looking at these
eight bowling scores,
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the average is higher than every value but
the highest.
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In this case, instead of using
the average to find the middle,
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it might be better to use the median.
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The median represents
the middle value in a data set.
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If your data set has an even number of
values and thus no true middle value,
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then the median is the average
of the two middle values.
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So for our bowling data set,
the median value would be 115, which
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does a much better job of representing
the middle than the average did.
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The last way we can try and
find the middle is to use the mode.
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The mode is them most frequent
value in our data set.
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In our bowling data set, there's only one
repeated value, so our mode has to be 90.
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Back in the spreadsheet, let's calculate
these values for our data set.
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Let's add the labels starting at A5,
average,
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median and mode.
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And then let's highlight those labels and
hit command or ctrl B to make them bold.
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Then in column B let's use functions
to figure out these values.
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In B5, let's type =AVERAGE.
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Hit Enter to select it, paste in our
range, hit Enter again and there we go.
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Now let's do the same thing for
the median and mode.
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Type in the function,
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paste in the range, and hit Enter.
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And there we go, except for the mode,
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looks like it's not using
the right data type.
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So let's click this button up here, and
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instead of Automatic
let's set it to Duration.
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There we go.
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All right, not only do we have information
about the edges of our data but
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now we have a pretty good
idea of where the middle is.
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If you'd like to learn more about mean,
median and
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mode, check out the teacher's notes.
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Coming up, we'll look at a few ways
to figure out the spread of our data.
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