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WHAT DO THEY ALL MEAN?

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Mode. Mean. Range. Median. WHAT DO THEY ALL MEAN?. A number that helps describe a set of data is an AVERAGE! Sometimes called a MEASURE OF CENTRAL TENDANCY. ALL OF THESE ARE AVERAGES:. MEAN MEDIAN MODE. We use the word the wrong way when we ask a teacher, “What’s my average?”. - PowerPoint PPT Presentation

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Page 1: Mean

WHAT DO THEY ALL MEAN?

Page 2: Mean

A number that helps describe a set of data is an AVERAGE!AVERAGE!

Sometimes called a

MEASURE OF MEASURE OF CENTRAL TENDANCYCENTRAL TENDANCY

Page 3: Mean

ALL OF THESE ARE AVERAGES:

•MEAN

•MEDIAN

•MODE

We use the word the wrong way when we ask a teacher, “What’s my average?”

What we should say is, “What’s my mean?”

Page 4: Mean

MeanThis is what we usually mean when we say “What’s my average.”

We could say, “What grade do I normally get?”

Page 5: Mean

How is the mean of a set of numbers found?

• Add all the numbers in the set together.

• Divide the sum by the number of data items in the set.

• The quotient is the mean of the set of numbers.

• Example: 10, 18, 12 and 16– Add 10 + 18 + 12 + 16 = 56– Divide 56 by 4– The mean is 14

Page 6: Mean

Median

• Is the number that is in the middle of a set of numbers.

• Half the numbers are below the median and Half the numbers are above the median

Page 7: Mean

How is the median of a set of numbers found?

• Arrange the numbers in the set in order from least to greatest.

• The middle number is the median of a set of numbers.

• If more than one number is in the middle of the set of numbers, the mean of those two numbers is the median of the set of numbers.

Page 8: Mean

Your grades on five tests:

95, 87, 92, 100, and 85

Put them in order from least to greatest

85, 87, 92, 95, 100

The middle number is the median

Your median test grade is 92 – half the time you score below 92 and half the time above 92

Page 9: Mean

Your grades on six tests:

95, 85, 87, 92, 100, and 94

Put them in order from least to greatest

85, 87, 92, 94, 95, 100

The middle is between 2 numbers

The median is the mean of 92 and 94

Or

92 + 94 = 186

186 divided by 2 = 93

Page 10: Mean

ModeThe number in a data set that occurs most often

Your grades: 95, 87, 85, 100, 100

Your mode is 100

Most of the time you get a 100

Page 11: Mean

How do I identify the mode of a set of numbers?

• Arrange the set of numbers in order from least to greatest.

• The number that occurs the most often is the mode of that set of numbers.

Page 12: Mean

You don’t have to have a mode…….

Some data sets have no mode or no number that occurs more than others

Some might have two modes

Page 13: Mean

Another way to describe data

Asks the Question:

How spread out is my data?

Page 14: Mean

How is the range of a set of numbers identified?

• Arrange the numbers in the set in order from least to greatest.

• Subtract the lowest number from the highest number in the set of numbers.

• The difference of the two numbers is the range of a set of numbers.

Page 15: Mean

Back to your test Scores:

95, 87, 92, 100, and 94

Your highest score is a 100

Your lowest score is 87

Your range is 100 – 87 = 13

The range = 13

Page 16: Mean

It’s Time To Practice!Number of pets owned by 7 students:

2, 1, 1, 4, 3, 2, 1

What is the mean 2

What is the median 2

What is the Mode 1

What is the Range 3

Page 17: Mean

4 ways to describe dataThe Mean – what we usually think of as the average…..

The Median – The middle number in a data set…..50% of the numbers are above and 50% are below the median

The Mode – The number that occurs most often…..

The Range – the difference between the smallest and bigest number…..