Measures of Central Tendency

Measures of Central Tendency

Mean

The mean of a data set is also the average

1. Add up all of the numbers in a data set

2. Divide the sum by how many numbers you added together

   1. Ex: In the data set {1, 5, 6}, there are 3 numbers

      1. This means you will divide by 3

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Consider the data set {4, 9, 6, 2, 2, 8, 10}

What is the sum of all the numbers?

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Consider the data set {4, 9, 6, 2, 2, 8, 10}

How many numbers are in the data set?

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Consider the data set {4, 9, 6, 2, 2, 8, 10}

What is the mean of the data set? Round your answer to the nearest tenth.

Median

The middle number in a data set

1. Order the data set from least to greatest

2. Cross off the numbers starting from the outside and working towards the middle.

   1. Ex: in the dataset {3, 4, 6, 8, 10}, I would cross off 3 and 10, then 4 and 8, and then I would be left with 6- my median!

Median

The middle number in a data set

1. Order the data set from least to greatest

2. Cross off the numbers starting from the outside and working towards the middle.

   1. Ex: in the dataset {3, 4, 6, 8, 10, 12}, I would cross off 3 and 12, then 4 and 10, then...

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Consider the data set {5, 4, 4, 8, 3, 6, 2}

Order the set from least to greatest.

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Consider the data set {5, 4, 4, 8, 3, 6, 2}

Order the set from least to greatest.

Which two numbers will you cross off first to find the median?

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Consider the data set {5, 4, 4, 8, 3, 6, 2}

Order the set from least to greatest.

Continue crossing off numbers until you get to the middle. What is the median of the data set?

Median

The middle number in a data set

Ex: in the dataset {3, 4, 6, 8, 10, 12}, I would cross off 3 and 12, then 4 and 10, then...
I can't cross out 6 and 8, because then I would have no numbers left!
***If you are left with two middle numbers, then take the average of the two.

Median

The middle number in a data set

Ex: in the dataset {3, 4, 6, 8, 10, 12}, I would cross off 3 and 12, then 4 and 10, then...
6 and 8 are my two middle numbers, so to find the average:
6 + 8 = 14
14 / 2 = 7
7 is the median of this data set!

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Consider the data set {5, 4, 4, 8, 3, 6, 2, 9}

Order the set from least to greatest.

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Consider the data set {5, 4, 4, 8, 3, 6, 2, 9}

Order the set from least to greatest.

Which two numbers will you cross off first to find the median?

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Consider the data set {5, 4, 4, 8, 3, 6, 2}

Order the set from least to greatest.

Continue crossing off numbers until you get to the middle. What two values are you left with?

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Consider the data set {5, 4, 4, 8, 3, 6, 2}

Order the set from least to greatest.

Take the average of those two numbers. What is the median of the data set?

Mode

The number that occurs the most.

1. Order the data set from least to greatest.

2. Determine which number(s) you see the most of.

***Note: there can be no mode, one mode, or more than one mode.

Fill in the Blanks

Consider the data set {4, 9, 6, 2, 2, 8, 10}

Order the set from least to greatest.

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Consider the data set {4, 9, 6, 2, 2, 8, 10}

Order the set from least to greatest.

Determine which number occurs the most frequently. What is the mode of the data set?