Bar Graphs SCMP Summer 2008

What is the day of your birth?

Ø  On a post-it note record the month of your birth and your name on the bottom in small print.

Ø  In LARGE print record the DAY you were born in the middle of the post-it note.

Ø  Place your post-it in the appropriate place on the bar graph.

What is your favorite strand to teach?

(Number Sense * Algebra and Functions * Measurement and Geometry * Statistics, Data Analysis and Probability * Mathematical Reasoning)

Ø  Place your post-it in the appropriate place on the bar graph.

Supplies needed: Large poster for class BAR GRAPH, post-it notes, poster pens and smaller individual version of the bar graph.

Ø  Create a class bar graph on large poster paper for a question of your choice. (i.e. What month were you born? What day of the week were you born? What is your favorite subject in school? What is your favorite winter sport? What is your favorite super hero?)

Ø  Give each student a post-it note and have them record their month of birth and name on the bottom in small print and the DAY they were born in very large print in the middle.

Ø  Before having the students place their post-it notes on the graph, ask them how likely they believe it is that someone in the class has the same birthday as themselves. Have students guess a percent such as 5% (very unlikely), 10% (unlikely), 50% (fairly likely) or 75% (very likely).

Ø  Have the students place their post-it in the appropriate column of the bar graph.

Ø  To summarize ask the students questions such as the following:

How many people…

1.  were surveyed?

2.  were born the same month as you?

3.  were born on the same day as you?

4.  What month(s) had the most births?

5.  What month(s) had the least births?

What fraction of the people…

6.  were born in the most popular month(s)?

7.  were born in the least popular month(s)?

What percent of the people…

8.  were born in the spring (March, April and May)?

9.  were born in the summer (June, July and August)?

10.  were born in the fall (September, October and November)?

11.  were born in the winter (December, January and February)?

12.  Write three statements about the information in the graph. (i.e. _____ percent of the people were born in the spring.)

13.  Were you surprised by any of your results?

Ø  The statistical probability that someone shares the same birthday as yourself is about 50% at 22 people.

Therefore, in a room of 65 people the probability of having a matching birthday is nearly 100%.

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