Aim: Can I display and analyze data using Histograms?

SWBAT: Define and create a histogram based on data.

Do Now: Compare the 2 charts below, how are they different? Is the second chart correct?

How are these bar charts different?

1- The first chart does not have an amount on the x-axis

2- The bars on the third chart are touching

3- The third second chart deals with intervals (from/to)Notice that the intervals overlap…OOOPS!

Intervals for each bar

OVERLAP- OOPS!

Colors represent bars – Bars do not touch

How Histograms are Unique

• Intervals of equal size• The bars of information touch

Would these Intervals Work for a Histogram?

• 1 - Ages of students: (6-10), (11-15), (16-20), (21-25)

• 2- Ages of workers: (16-20), (20-25), (25-30), (30-35)

• 3- Dollars spent: (1-25), (26-100), (101-250), (251-1,000)

• YES OR NO, AND WHY ?

Here are some rules for using Intervals with Histograms• 1- Ages of students: (6-10), (11-15), (16-20), (21-25) YES• 1- Equal Intervals and 2- No Overlap – Good to go!

• 2- Ages of workers: (16-20), (20-25), (25-30), (30-35)• Overlap of ages – This will not work!

• 3- Dollars spent: (1-25), (26-100), (101-250), (251-1,000)• These intervals are not equal!• Setting up Intervals is tricky! Setting up Intervals is tricky! • Be careful!Be careful!

So what are Histograms used for and how do they differ from Bar Charts? • Bar Charts display and compare data

• So do histograms but we use equal Intervals of values or ranges

Definition of a Histogram

• A histogram is a bar graph that shows the frequency of data within equal intervals. There is no space between the bars in a histogram.

Exercise

• 1. These are the number of laps students ran one day around Phoenix House. We will make a histogram of the data together.

• 4, 7, 9, 12, 3, 6, 10, 15, 12, 5, 18, 2, 5, 10, 7, 12, 11, 15• First, we organize into a chart with Intervals and Frequency.

INTERVALS (From/To) FREQUENCY/ Laps Run

0-4

5-9

10-14

15-19

Exercise

• 1. These are the number of laps students ran one day around Phoenix House. We will make a histogram of the data together.

• 4, 7, 9, 12, 3, 6, 10, 15, 12, 5, 18, 2, 5, 10, 7, 12, 11, 15• First, we organize into a chart with Intervals and Frequency.

INTERVALS (From/To) FREQUENCY/ Laps Run

0-4 3

5-9 6

10-14 6

15-19 3

Histogram – Let’s Draw

Let’s try on our own with some baby Tigers and how much they weigh

• Baby Tigers weighing in: 2, 3, 7, 8, 8, 9, 10, 12, 12, 16, 16, 17, 18 , 19, 20

• When done: Work with your assigned classmate and then continue on with your worksheet if you are confident you can:

1- Set up Intervals2- Draw a vertical and horizontal axis3- Put the intervals on the horizontal (bottom) axis

Interval (pounds) Frequency

0-3

4-7

8-11

12-15

16-19

EXIT TICKET

• Why use a histogram or a bar chart?• Think of a reason you would prefer to see

numbers or data in a histogram and write it down.