Histograms &
Comparing Graphs
Focus 6 Learning Goal – (HS.S-ID.A.1, HS.S-ID.A.2, HS.S-ID.A.3, HS.S-ID.B.5) =
Students will summarize, represent and interpret data on a single
count or measurement variable.
4
In addition to level
3.0 and above and
beyond what was
taught in class, the
student may:
· Make connection
with other concepts
in math
· Make connection
with other content
areas.
3
The student will summarize,
represent, and interpret data
on a single count or
measurement variable.
- Comparing data includes
analyzing center of data
(mean/median), interquartile
range, shape distribution of a
graph, standard deviation
and the effect of outliers on
the data set.
- Read, interpret and write
summaries of two-way
frequency tables which
includes calculating joint,
marginal and relative
frequencies.
2
1
The student will be
able to:
- Make dot plots,
histograms, box
plots and two-way
frequency tables.
- Calculate
standard deviation.
- Identify normal
distribution of data
(bell curve) and
convey what it
means.
With help from
the
teacher, the
student has
partial success
with summarizing
and interpreting
data displayed in
a dot plot,
histogram, box
plot or frequency
table.
0
Even with
help, the
student has
no success
understandin
g statistical
data.
What are Histograms?
A
histogram is a graphical
display of data using bars of
different heights.
 Each bar represents the
frequency of an event
occurring in an equal sized
interval.
 Histograms are used to
analyze large sets of
quantitative data.
Frequency
of
Shapes of Histograms

What do you notice about the possible shapes of histograms
compared to the possible shapes of dot plots?
How to make a histogram:
1.
2.
Determine the range of your data.
1.
Lowest number 44. Highest number 71.
2.
Range = 27
Determine appropriate equal intervals.
1.
3.
5 numbers per interval.
Make a frequency table with the intervals.
1.
Put a tally mark in the appropriate interval for
each number.
2.
Verify that you have the same number of tally
marks as you have items of data.
Daily high temperatures in
degrees Fahrenheit:
63 70 64 71 71 62 68 67 68
72 65 62 59 58 60 59 56 53
51 55 56 50 53 57 55 50 46
49 46 52 48 44
How to make a histogram:
4.
Create a graph. Label the xaxis with the intervals from the
frequency table. Label the yaxis “Frequency.”
5.
Draw each bar to the
appropriate height.
6.
The bars must touch each
other, no gaps between bars
unless there are no data
points for that interval.
F
R
E
Q
U
E
N
C
Y
Comparing Graphs

The dot plot shows the ages of people who are
grandparents living in the Aprende
neighborhood.

How does a dot plot compare to a histogram?

When is it better to use a dot plot?
Comparing Graphs

Box plots can be created side
by side to compare two sets of
data on the same scale.

This box plot shows average
monthly rainfall for Miami, FL
and New Orleans, LA.

Which city shows a greater
range in average monthly
rainfall?

Explain how the parallel box
plots makes it easy to compare
the ranges in this case.

How do the maximums, minimums,
and the medians of the two data
sets compare?
Comparing Graphs

The test scores of students in a math class are as follows:
80, 72, 82, 80, 80, 80, 88, 88, 84, 92, 92, 96, 70, 90, 98, 92, 88, 92, 90, 80, 84

Which graph is best for finding out the
most common test score?

Which graph is best if you want to know
how many people scored a B on the test?

Which graph is best for a teacher who
wants to know the range of scores for the
bottom 25%, the middle 50% and the top
25%?