WEBVTT
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The table shows the weights, approximated to the nearest kilogram, of 40 students.
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How many students weigh 45 kilograms or more?
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So the key to answering this question is the fact that we’re looking for students that weigh 45 kilograms or more.
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Now, if it just asked for the students who weighed 45 kilograms, then we wouldn’t be able to answer it.
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And the reason we wouldn’t be able to answer it is because this is a grouped frequency table.
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And that means we don’t know the exact values of the students.
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So we know that there are seven between 45 and 49.
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But we don’t know what the individual weights of those seven students are.
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So if we’re looking for 45 kilograms or more, then the only two columns that we’re interested in are the two that I’ve ticked.
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And that’s 45 to 49 and 50 to 54, because these are either 45 kilograms or more.
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So therefore, to work out how many students weigh 45 kilograms or more, what we need to do is add seven and nine.
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We’re gonna add seven and nine because we’ve got seven students who weigh between 45 and 49 kilograms.
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And we have nine students who weigh between 50 and 54 kilograms.
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So therefore, when we add these together, we get 16.
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So we can say that 16 students weigh 45 kilograms or more.