Transcript Thursday, October 14

Friday, October 15
Today’s Agenda
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1.
Fill in Planner
1.
2.
2.
Bell Work (Write these numbers from least to greatest)
1.
2.
3.
3.
Practice 2-7
Test will be Thursday 10/21
2.4, 9.8, 3.6, 7.5, 1.9
2 ½, -3 ½, 4 ½, 1 ½
-12, 14, -3, 1, -8, 7, 0
Today’s Objective: SWBAT find mean, median, mode,
and range and make and use stem and leaf plots.
Vocabulary
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Measures of central tendency: A way to
organize and summarize data.
Mean: Mean is best used to describe a set of
data that has no outlier. It is found by dividing
the sum of the data items by the total number
of data items.
outlier: a data value that is much higher or
lower than the other data values in the set.
Vocabulary
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Median: the middle value in the set when the
numbers are arranged in order. For a set containing
an even number of data items, the median is the mean
of the two middle data values. Median is best used to
describe a data set that does have an outlier.
Mode The data item that occurs the most often. It is
possible to have no mode, one mode, or more than
one. Mode is best used to describe data when the
values are not numeric or when looking for the most
popular item.
Example 1: Find the mean, median,
and mode.
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Hourly wages of employees at a local restaurant are $6.25, $7.10, $8.12,
$7.15, $6.75, $5.95, $8.05. Find the mean, median mode and range.
Which of these measures of central tendency best describes the data set?
6.25  7.10  8.12  7.15  6.75  5.95  8.05
7
49.37
7
 $7.05
5.95, 6.25, 6.75, 7.10, 7.15, 8.05, 8.12
$7.10 is the median value.
List the date in order
from least to greatest
For this data set, there is no mode because no value appears more than once.
Example 2: Solving an equation
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Suppose your grades on your last three algebra
tests are 80, 93, and 91. What grade do you need
on the next test to have a 90% average?
80  93  91  x
 90
4
80  93  91  x  360
Simplify
 80  93  91  x 
4
  90  4
4
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Multiply both sides of the equation by 4
to clear the denominator
264  x  360
264  264  x  360  264
x  96
Subtract 264 from each side
You need at least a 96% to have an average of 90% on your tests.
Stem and Leaf Plot
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A display of data made by using the digits of
the values. The last digit is the leaf and all the
digits to left of the last digit are the stem.
51, 84, 86, 88, 92, 99, 113,
114, 121, 122, 124, 138, 144,
147, 148, 151
Today’s Objective: SWBAT find
mean, median, mode, and
range and make and use stem
and leaf plots.