Transcript Boxplots

Ed took 5 tests and his average was 85. If his
average after the first three tests was 83, what’s the
average of the last two tests.
On Thursday, 20 out of 25 students took a test and their
average was 80. On Friday, the other 5 students took it
and their average was 90. What was the class average?
Finishing
Mean/Median
Examples
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Average salaries of professional football
players.
Scores on a test when there’s one that
hasn’t been made up yet.
Average salaries of 1st year teachers
mean
median
mod e
mode median mean
mean median mod e
Boxplots
Boxplots
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Provides information about the
center, spread, and symmetry
(skewness) of the data.
Multiple boxplots can be used to
compare data.
Constructing a boxplot.
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Find the five number salary
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Minimum
Q1
Median
Q3
Maximum
Plot on number line.
Box in the IQR and draw whiskers to
the min & max.
5, 8, 13, 17, 22, 24, 25, 27, 29, 30
8, 10, 22, 24, 25, 25, 26, 27, 45, 72
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Graph & Describe
Outlier
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A value is considered an outlier if it
is more than 1.5 IQR away from the
closest end of the box.
5, 7, 9, 9, 10, 11, 13, 17, 29
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Find if there are any outliers.
Using the Calculator.
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Put data in List
Press 2nd stat
Turn plot 1 on and choose boxplot
Zoom 9
22, 27, 33, 39, 57, 88, 110
Comparative
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Measure your longest finger.
Create boxplot of girls vs boys.
Describe
Variation
Standard Deviation
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This is a measure of the average
distance of the observations from
their mean.
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Variance – it is the average of the
squared distance from the mean.
Homework
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Page 71 (89, 91, 93, 95, 97, 105,
107-110)
Bring Candy for tomorrow!