Advanced Math Topics
2.4 Cumulative Frequency Histograms &
Polygons
If you do not use stem and leaf add the part
about misleading graphs to this ppt
Normal Curve
A radar set up on Highway 580 for one hour clocked
and recorded car speeds between 52 and 82 mph. The
How will the graph look? scatter plot is shown below.
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This is an example of a normal
curve (normal distribution),
Also known as the “Bell Curve.”
Many things that occur in
nature have a normal
distribution.
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Would these have a normal distribution?
The useful life of an auto battery with time along the horizontal axis.
Yes!
The number of students per class with # of students on the horizontal axis.
Depends, some classes(PE) may throw it off)!
The attendance at AT&T Park for Giants with the amount of people
on the horizontal axis.
No, the attendance is too consistent!
http://sports.espn.go.com/mlb/attendance
Steps to Create a Cumulative Frequency Histogram
1) Create a new column “Cumulative Total.” Add all previous
frequencies and put this number in the row.
2) Follow the steps to create a histogram
Cumulative frequency histogram: a histogram displaying accumulated figures
Cumulative Frequency Histogram
How many recruits weighed 170
lbs. or less?
Weights of 250 Army Recruits
Weight
(lbs.)
131-140
141-150
Frequency
23
43
Cumulative
Frequency
23 + 43 = 66
59
66 + 59 = 125
161-170
69
125 + 69 = 194
56
194 + 56 = 250
Sometimes we ask questions like…
“How many are less than
or equal to a certain measurement?”
250
240
23
151-160
171-180
280
194
200
Cum.
Freq.
160
125
120
80
66
40
23
131-140
151-160
171-180
141-150
161-170
We can answer this by accumulating the frequencies.
Weight
Steps to Create a Cumulative Frequency Polygon
1) Find the cumulative total for each row
2) Create axis and intervals just like a histogram
3) Place a point for each cumulative frequency on the
right side of the interval
Why the right?
Because the frequency includes all numbers at or below
the highest number in the interval
4) Connect the points
Cumulative
Frequency
Cumulative Frequency Polygon
23
23 + 43 = 66
280
240
Cum.
Freq.
250
200
194
160
.
125
120
80
40
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66
.
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66 + 59 = 125
.
125 + 69 = 194
194 + 56 = 250
A line graph that answers the question
“How many recruits weigh less than or
equal to a certain weight?”
Create the same axes and scales,
place a point on the upper limit for each interval
at its cumulative frequency and connect them.
There were 125 recruits 160 lbs. or under.
23
131-140
151-160
171-180
141-150
161-170
Weights
There were 0 recruits 130 lbs. or under.

Assignment
P. 61 – 67
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#3, 4, 12, 14a, 14b, 15
Together P. 67 #14a
We have 3 missing protractors