Earth Math
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ALGEBRA LAB

# Nitsáhákees (thinking)

Observations regarding population increase/decrease

Questions:

A.  Do you think that population in the 4-corners area is increasing or decreasing?

B.  What have you noticed recently that led you to your answer to A?

C.  How do you think population change might influence your life?

D.  Do you think population in the Navajo Nation is increasing or decreasing?  Why?

E.  How can we use mathematics to study population change?

# Nahatá (planning)

Mathematical Topics

Learn or review mathematical concepts and skills needed to study population change.  See Menu to the left.

Information

The data in the table below are from Chapter Images, 1996, Window Rock.

 YEAR POPULATION, SHIPROCK CHAPTER 1980 6,103 1990 7,850 1997 8,615

# Iiná (living)

Apply mathematical knowledge and Tool Chest operations to analyze population changes in the Shiprock Chapters.  Answer the questions below.

Questions:

1. Make points from these using the variables "x" as first coordinate and "S" as  second coordinate.  Let x = 0 in 1980, and in general, x = number of years after 1980; "S" will denote the population of Shiprock.  Then plot the points on the Plot screen.

2. Use linear regression to find the linear equation whose graph passes through these points.  Graph the line and print the screen.

3. Explain what your line tells you in terms of Shiprock Chapter population.

4.   Is the population of the Shiprock Chapter increasing or decreasing?

5.  What is the annual rate of increase/decrease?

6.  Use your equation to estimate the population this year.  In the year 2020.  In the year 2040.  Then mark the corresponding points on your graph.

7.  When will the population reach 12,000?  16,000?

# Sihasin (assurance)

Examine solutions and implications.

A.  Do you think that linear equations are good to use for this study?

B.  How can we know a reasonable type of equation to use?

C.  How long do you think the model will be accurate?

D.  How do you think the predicted increase/decrease in population effect the areas and life in the Shiprock Chapters?