Histograms and Line Graphs

HistogramA type of bar graphSeparates information into categories

The bars are connected*Uses intervalsYou need a frequency table to make a histogram

Steps to Take:First, put the data in order from

least to greatest.Second, determine the interval

you need to use.Third, make a frequency table to

organize your information.Fourth, make your histogram.

Example:40,13, 35, 27, 41, 34, 21, 37, 40, 12, 33Step 1:

◦ 12,13, 21, 27, 33, 34, 35, 37, 40, 40, 41Step 2:

◦ Use intervals of 10Step 3:

◦ Interval Frequency0-9 010-19 220-29 230-39 440-49 3

Example 1 (continued)

0 10 20 30 40

INTERVAL

FRE

QU

EN

CY

1

2

3

0

4

50

Problems:Make a histogram with the

following data: 13, 24, 12, 6, 9, 30, 37, 34, 16, 13, 4, 8, 0, 20

Make a histogram with the following data: 106, 110, 90, 83, 79, 99, 110, 107, 105, 103, 124, 148

Line GraphGraph with a line*Shows change over time

Points are placed on a graph and connected by (straight) line segments

Steps to Take:First, organize the data into a

chart.Second, place the change on the

vertical axis and the time on the horizontal axis.

Third, determine an appropriate interval for both.

Fourth, plot your points.Fifth, connect each point to the

next with a line segment.

Example:A child recorded his height since 2007. In 2007,

he was 50 inches tall. In 2008, he was 54 inches tall. In 2009, he was 56 inches tall. In 2010, he was 60 inches tall. In 2011, he grew to 65 inches tall. In 2012, he was 68 inches tall.

Step 1◦ Year Height

200750200854200956201060201165201268

Example:Step 2: Years will go on bottom

and height will go on the left.Step 3: Years will go up by 1.

Height will go up by 10.

Example:Steps 4 and 5

Year

2007 2008 2009 2010 2011 2012

Heig

ht

(in inch

es)

0

10

20

30

40

50

60

70

ProblemsMake a line graph with the

following data: In 1990, there were 40 animals at the zoo. In 1995, they had 56 animals. In 2000, the number had dropped to 23 due to a hurricane the previous year. In 2005, a new shipment of koalas boosted the number to 43. In 2010, the number of animals was all the way up to 62.

ProblemsMr. Plyler has taught several different

class sizes over the past eight years. In 2005, he had 32 students. The next year he had 30. The following year he had 28. When he moved to Humboldt in 2008, he had 25. In 2009, he had 22. In 2010, his class size dropped to 18. However, in 2011, due to a budget cut, his class sizes rose to 23. Then he moved to Medina in 2012 and has a class size of 28. Make a line graph with this information.