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Discover the significance of graphs in organizing and interpreting data easily. Learn about the parts of a graph - independent and dependent variables - and practice plotting data to understand trends. Explore different types of relationships depicted in graphs and compare rates of change visually to grasp data analysis effectively.
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Graphing Makes our life simpler!
Why do we use graphs? • It’s an organized way to express data • Allows for easy interpretation of the data
What are the parts of a graph? • Independent variable: • Goes on “x” (horizontal) axis • Controlled by the experimenter • Dependent variable: • Goes on “y” (vertical) axis • Result of applying the independent variable Let’s do a practice problem!
Determining variables • The table shows data collected on the pH of a lake in the Adirondacks over 16 years. • Based on the table, what is the independent variable and what is the dependent variable? • ANS: IND = year DEP = pH level
Setting up your graph • Now we know the variables, so we know where to plot them • On X axis (independent) • Year • On Y axis (dependent) • pH pH Year
Plotting your data • You are now able to plot your data pH Year
Interpreting your graph • What is the trend in pH of this lake over 16 years? • pH decreases • pH becomes more acidic • What environmental condition(s) could’ve caused this trend? • Burning fossil fuels • More factories in the area • More industrialized • More cars
Types of relationships determined by graphs • Direct relationship • BOTH variables INCREASE • Can you sketch a graph that shows this?
Types of relationships determined by graphs • Indirect relationship: • Independent variable increases, dependent decreases • Can you sketch a graph with this relationship?
Types of relationships determined by graphs • Cyclic relationship: • Shows repeating of same event over time • Can you sketch a graph that shows a cyclic relationship? Time
Types of relationships determined by graphs • Stable (no change): • Dependent variable stays the same as independent increases • Can you sketch a graph showing stability?
Comparing rates of change using graphs • The angle of plotted line tells us the rate • The STEEPER the line, the FASTER the rate • Which of the following graphs has a faster rate?