ShmoopTube

00:03

Okay, let's get down to the shmoopy question.

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Tamara, a runner in her high school track team, posted lap times of 24, 18, 21, 15,

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and 18 seconds on her practice runs.

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If her coach allowed her to pick the mean, median, or mode of this set for evaluation

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of her fastest times, which should she use to represent her time?

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Here are the possible answers:

00:33

Clearly Tamara needs to work on her pacing.

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Like... come on... a 15 second lap and a 24 seconder?

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What is she... downing Big Macs between laps?

00:41

Okay... now what's this... semi-weird question asking?

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Well, 3 things, really... all involving vocab words we have to know:

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That's mean... median... and mode.

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And there's a curve ball thrown in here...

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in that we want the lowest number...

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The lowest number represents the shortest time it took Tammy-pie to run her lap.

01:02

Smaller is better.

01:04

So there are 3 parts to this problem.

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First, we calculate the mean or average... which is:

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24 + 18 + 21 + 15 + 18, which totals 96.

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Divide the 96 by 5, since we're averaging 5 elements...

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...and we get 19.2 as the mean.

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So Tamara's mean time based on this assessment of her fine athletic field efforts is 19.2.

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We're a third of the way there. Second, we calculate the median.

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Median is just a fancy way of saying "the middle."

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Once we order the numbers from smallest to biggest...

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...we can see that the middle number is 18.

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So the median has beaten out the mean by 1.2 seconds.

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But we have a third calculation we need to apply... mode.

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In other words, what number occurs most frequently?

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Doesn't matter how big it is. For example, if we're looking for the mode among 99,

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98, 97, 96, 2 and 2...

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Our mode is 2. Score one for the little guy. Right. So what's the mode here? 18.

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It appears we have a tie.

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Median and mode... going to sudden death...

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So the answer is D, "either"...

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...that is, the median and mode are both 18.

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