Note 1'2

1
Note 1.2

• Measures of Central Tendency and Range

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1.2 Measures of Central Tendency and Range

• Four measures to help you describe data
• Mean
• The Arithmetic Average (You add all the numbers
  up and divide by the total numbers in the data)
• Say My mean math teacher made me average my
  grades.

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1.2 Measures of Central Tendency and Range

• Median
• The middle value
• Arrange the data from least to greatestthe
  number in the middle is the median (or average
  the two middle numbers)
• Say Watch out for the median in the middle of
  the road

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1.2 Measures of Central Tendency and Range

• Mode
• Mode is the number that repeats most often
• If no number repeats, you have NO MODE
• Say MOOOOOde is MOOOOOST often

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1.2 Measures of Central Tendency and Range

• Range
• The range is the difference between the greatest
  and lowest values in the data.
• You SUBTRACT the Maximum and the Minimum numbers
• Say Max minus Min will get the Range in.

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What are measures of central tendency?

• Since the mean, median, and mode are different
  Centers of data, they are all called measures of
  central tendency.
• The range is NOT a measure of central tendency!

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Its time for SHOWDOWN!

• Pick up a white board and a marker.
• When the question appears, write down the answer
  on your board.
• When the teacher says, Showdown, hold up your
  answer!

8
What measure of central tendency best represents
the data?

• SHOWDOWN!
• (Mean, Median, or Mode)
• The middle value of hourly wage of employees at a
  convenience store.
• The number of people with green eyes among your
  classmates
• The favorite subject among your friends.
• The average number of hours spent each week at a
  health club by members
• The middle value of teacher salaries.
• The average height of the basketball team
• The most checked-out book at the library
• The most popular politician after a debate
• The advertised March temperature in a resort
  brochure
• The favorite movie among your friends

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Find the Mean, Median, Mode, and Range

• 4 3 6 5 5 7 5
• 40 45 40 30 35 25 55 20
• 2.1 2.5 2.4 2.8 1.9 3.2

Mean _______________ Mode ________ Median
____________ Range _______
5
5
5
4
Mean _______________ Mode ________ Median
____________ Range _______
36.25
40
35
37.5
2.48
none
Mean _______________ Mode ________ Median
____________ Range _______
2.45
1.3
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SHOWDOWN!

• 240, 231, 358, 226, 239, 258, 214, 254
• Mean
• Median
• Mode
• Range
• 0.6, 0.5, 0.9, 1.2, 0.3, 1.1, 0.2, 0.8
• Mean
• Median
• Mode
• Range

11
Ricardo earns a base salary of 500 a week plus a
weekly commission. Hehas earned a commission of
325, 460, 280, 400, 380, and 250 eachweek
for the last six weeks.
12
Ricardo earns a base salary of 500 a week plus a
weekly commission. Hehas earned a commission of
325, 460, 280, 400, 380, and 250 eachweek
for the last six weeks.
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Homework

• Label your paper
• 1.2 Pg. 12 1-4, 6-10, 12-14
• Due ___