Lesson: Checking County Numbers

Connecting Math to Civics


Using the San Mateo County Statistics information page, students will learn how to create graphs from tables and interpret data presented in a variety of different formats.


Grade Levels: 4th- 8th




Time: two or three class session (approx.)



San Mateo County Statistics Information page (included)

Graphing paper



Rulers or straight edges

Paper & pencils

* Microsoft Excel or similar spreadsheet program (to be used with older children)

Overhead of San Mateo County Statistics Information pages

Student copies of San Mateo County Statistics Information pages




1.     Present overheads of San Mateo County Statistics pages.  Talk about the information that is presented and the format that it is presented in (bar graphs, percentages and tables).  Ask students what they can tell you about the information presented.  Help them to make statements based on the data and compare and contrast information (e.g. most of the people who live in San Mateo were born here).


2.     Instruct students to work in teams of 2 to create 5 statements about the information that is presented on either of the SMC statistics pages. Encourage them to make comparisons between the various data presented in a table, chart or graph. Share out the information that the students discovered.


3.     Instruct students that they will now take some of these data and present them in a different format. Begin with a bar graph.  Show students how the 2000 Population by Age Group is measured in thousands and that the graphÕs scale is in increments of 2 thousand people.  Using graph paper and pencils, ask students to construct a similar bar graph using the information presented in the County Jobs and Employment table.


4.     Instruct students to create a circle graph (pie chart) using the County Population percentages (use only the native born persons and foreign born persons percentages). Direct students to use their protractors and compasses to create their circle graphs (a pre-drawn circle for younger studentsÕ graphs is recommended). Help children to first find out the degrees of the circle that will be needed for the two pieces of data. Note: Students can use ratios such as dividing 360 by 100 to figure out how many degrees a percentage point equates to and then multiplying that number (3.6) by the actual data percentage (74.6% and 25.4%). Students can also create an algebraic equation such as x=n(360/100), where n is either 74.6% (native born persons) or 25.4%(foreign born persons) and X is the degrees of the circle allocated for that data percentage.


5.     Using a spreadsheet program such as Microsoft Excel, direct students to create simple spreadsheets from the San Mateo County Statistics data.  Create a computer-generated circle graph of the County Population data (used in the previous lesson).  How does it compare to the student-generated graphs? To create additional circle graphs, use the Education of Persons 18+ data or the 1990 percent Population by Race data.  The County Transportation data might also be interesting to put into a circle graph, especially given the way that this data is presented.  Ask why the bar graph looks so different and what decision was made to represent this data. Bar graphs can be made out of the table data.  Allow students to play around with various ways to represent the data once they understand how to create computer generated graphs.


6.     Direct students to write at least a paragraph analyzing the data with which they worked. They may want to raise additional questions based on what they discovered. 



CA Math Standards

Statistics, Data Analysis, and Probability

Grade 4: Students organize, represent, and interpret numerical and categorical data and clearly communicate their findings.

Grade 5: Students display, analyze, compare, and interpret different data sets, including data sets of different sizes.

Grade 6: Students compute and analyze statistical measurements for data sets.

Grade 7: Students collect, organize, and represent data sets that have one or more variables and identify relationships among variables within a data set by hand and through the use of an electronic spreadsheet software program.

Measurement and Geometry

Grade 4: Students demonstrate an understanding of plane and solid geometric objects and use this knowledge to show relationships and solve problems.

Grade 5: Students identify, describe, and classify the properties of, and the relationships between, plane and solid geometric figures.

Grade 6: Students identify and describe the properties of two-dimensional figures.