Mean_ Median_ Mode and Range by dffhrtcv3

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									Mean, Median and
Mode, and Range

Module 1, Lesson 4
Online Algebra 1
VHS@pwcs
Cami Craig
Numbers Everywhere

           Numbers are a great way to
               recognize trends and
             interpret data. One way
                to interpret is to use
                measures of central
               tendency. These are
             mean, median, mode and
                        range.
       Mean
 The mean is one of the most common statistics that we
      look at. You might know mean as the average.

To find the mean:
o Add up all of the data
o Divide by the number of items of data.

To find the mean of the numbers in the box above.
o Add up all the data 0 + 1 + 2 + 3 + 5 + 7 = 18
o Divide by the number of items of data: 18/6 = 3.
o The mean or average is 3.
                Median
     The median is a number that is the middle when the numbers are in
         order. How we find this is different if we have an even or odd
                       number of items in are data set.

For an odd number of items.                          For an even number of items:

•   Put the numbers in numerical order.              •   Put the numbers in numerical order.

•   Find the number in the middle, there will be     •   There will be 2 numbers in the middle. Find
    exactly one.                                         the sum of the 2 middle numbers and divide
                                                         by 2.
                                                     In the set of numbers:
In the set of numbers:
                                                                    1, 1, 2, 2, 4, 5, 8, 11
          2, 3, 5, 5, 6, 8, 9, 9 12, 13, 14
                                                     2 and 4 are in the middle. Notice that there are 3
    There are 11 numbers, so our 6th number will         numbers on each side of the 2 and 4.
    be the median. Notice that there are exactly 5
    numbers on either side of 8, or 6th number.      The 2 + 4 = 6, and 6/2 = 3, so 3 is the median.
          Mode

     The mode is the number that occurs the
                      most.
   In the set of numbers.                                     In the set of numbers:
 8, 9, 2, 5, 6, 6, 2, 9, 9,6, 6                              0, 1, 2, 4, 5, 7, 9, 3, 12
There are four 6’s therefore 6                          There are no numbers that repeat.
        is the mode.                                       Therefore there is no mode.

                           In the set of numbers:
                                  2, 2, 3, 3, 4, 5, 6
There are two 2’s and two 3’s. In this case we have more than 1 mode.
             The mode is both 2 and 3. (a double mode)
Range

o The range is the difference between the
  greatest and the least values of a set of
  data.
o Example: {6,3,10,14,2, 22,11}. The
  greatest value is 22 and the least is 2.
  The range is 22 – 2 which is 20.
o Example: {-10, 15, -32, 45, 23,20}. The
  greatest value is 45 and the least is -32.
  The range is 77. (45 - -32)
         Try it!
         Find the mean, median, mode, and range of each set of
         numbers.

{23, 15, 17, 19, 23, 16, 34}      {0, 20, 25, 42, 12, 25, 18,
                                               22, 16, 32}
      Mean: 21                            Mean: 21.2
     Median: 19                           Median: 21
       Mode: 23                             Mode: 25
     Range: 19                            Range: 42
       Mean, Median, Mode & Range
Remember:
o The mean is the average of a set of numbers. To find
  it add up the numbers and divide by the number of
  items in the data set.
o The median is the number in the middle when the
  numbers are in numerical order. If there is an even
  number, you need to find the sum of the 2 middle
  numbers and divide by 2.
o The mode is the number that occurs the most. There
  can be one mode, no mode or more than one mode.
o The range is the difference between the greatest and
  the least values in a set of data.
On your own


              Homework is
              Worksheet 1.4

								
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