Measures of Central Tendency

Measures of Central Tendency

• Mean• Median • Mode• Range

Mean:

• The mean is the mathematical average of a set of numbers.

• The mean is commonly referred to as the “average.”

• The mean is quick and easy to calculate.

• The mean is used in a variety of ways and in almost every industry.

Calculate the Mean

• What is the average age of our class?

• Ages: 11, 11, 13, 12, 12, 13, 12, 12, 12

• Mean = sum of ages/number of students

• Average age = 12

Mean

• A real world example of the Mean is Par.

• Par is the average expected score in Golf.

• If a hole is a Par 4, then the average expected score is 4 strokes.

Mean

• Companies use the mean age of their consumers to develop their advertising.

• Can you think of a commercial that was targeted towards you?

Mean

• Can you think of another example of how the Mean relates to the real world?

Median

• The median is the middle value of a set of data.

• Memorizing Tip: remember that the median is in the middle of the road.

Median

• The median is used in a variety of statistics.

• For example the median income in Alabama is $38,111 (U.S. Census Bureau).

• The median age in Montgomery, AL is 33.7 years old (U.S. Census Bureau).

Median

• Find the median for the set of data.

• Data set: 2, 5, 6, 7, 1, 3, 0, 8, 4

• Place in order from least to greatest and find the middle number.

• 0, 1, 2, 3, 4, 5, 6, 7, 8

• The median is equal to 4!

Mode

• The mode is the most frequently observed value in a data set.

• The most frequently printed words in English are: the, of, and, a , and to (www.duboislc.org).

Mode

• The most popular baby names in 2006 were Jacob, Emily, Michael, Emma, Joshua and Madison (Social Security

Administration).

Mode

• Find the mode for this set of data.• Data set: 2, 4, 3, 4, 3, 4, 4, 5, 4, 5, 5• The mode is 4, because it occurs the

most times.

Range

• The range is the difference between the largest and smallest values.

• Range of age: Oldest – Youngest.• Range of height: Tallest – Shortest.• Range of speed: Fastest – Slowest.• Can you think of a use for the range?

Range

• Those below the age of 5, or older than 50 should get vaccinated for the flu (www.cdc.gov).

• What is the range of age for those who don’t need to be vaccinated?

• 50-5=45

References• Income. Retrieved April 25th, 2008, from

http://www.census.gov/hhes/www/income/income04/statemhi.html.

• Key Facts About Seasonal Flu Vaccine. Retrieved April 25th, 2008, from http://www.cdc.gov/flu/protect/keyfacts.htm.

• Popular Baby Names. Retrieved April 25th, 2008, from http://www.ssa.gov/oact/babynames.

• The First 100 Most Commonly Used English Words. Retrieved April 25th, 2008, from

http://www.duboislc.org/educationwatch/first100words.html.