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this question gives you a frequency table and asks you
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to find the mean of the date of its describing
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in this table the values which I'll call X or
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equal to nine, 12 15 and 18. Um
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, the frequencies, which are called F, are
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equal to 43 There's three nines, five twelves 1
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15 and 1 18 Now we know that finding frequency
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are finding that mean X bar from a frequency table
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like this. We need to find the sum of
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all the of all the values times the frequencies over
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n and end is equal to the sum of all
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the frequencies. So let's ah, first, I'm
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gonna make it column Another column In this frequency table
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, it's X times F um, we'll have nine
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times three, which is 27 12 times five,
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which is 60 and and 15 times 1 15 and
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18 times 1 18 So these are all the values
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for X times f. And now what I want
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to do is at a row on the bottom where
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we add all of them up. This will be
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the total row. We don't really care about Thea
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. Some of the values that doesn't help us find
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the mean. Um, but we do want to
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know that some of the frequencies here three plus five
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plus one plus one that's gonna be 10 and some
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of the X times f values. If we add
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all those up, we're gonna get 120. So
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remember the sum of F. What we found here
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is the same thing is end. So now we
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know that n is equal to 10 and the sum
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of X times F is equal to 1 20 So
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when we plugged it into our mean equation will get
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that X bar Zagato 1 20/10 or just 12 and
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that's your