Tools of Environmental Science

Section 1: Scientific Methods How do we do environmental science? Scientific MethodS The Scientific Method is a Myth!—there is no single scientific method!

Experimental Method Observe & Ask Questions Research Hypothesize Variables Dependent Variable—DV (DRY) Independent Variable—IV (MIX) Groups Experimental group—gets the IV Control group—does NOT get the IV Lab Vs. Field Experiments

Collect, Organize, & Analyze Data Draw Conclusions Repeat Experiment Report Results

Correlation Method Examining associations between two or more events Must be careful! Correlation ≠ Causation

The Correlation Co-efficient The correlation coefficient ® measures the strength of association between two variables INSERT EQUQATION HERE   This value ranges between +1 and -1 and indicates how two factors can vary in relation to each other If r > 0 as one factor increases, the other factor will increase with it If r = 0 the two factors are not related If r < 0 as one factor increases, the other factor will decrease We must then evaluate whether the r value represents a true association between the variables or whether it is simply due to chance If the correlation coefficient is significant it indicates that there is a strong association between 2 variables Find the row for the correct degrees of freedom and determine whether the r value is significant at the 5% or 1% significance level If df – N – 2 5% chance that we could have gotten that r value due to random chance 1% chance that we could have gotten that r value due to random chance Significant association does not imply cause and effect Our value of 0.237 is not significant Correlation Between Variables Scatter plots: can be used to visualize the degree of correlation Correlation coefficient: measure of association between 2 variables r = 1 for perfect correlation r = 0 for no correlation

The Correlation Co-efficient The correlation coefficient ® measures the strength of association between two variables INSERT EQUQATION HERE   This value ranges between +1 and -1 and indicates how two factors can vary in relation to each other If r > 0 as one factor increases, the other factor will increase with it If r = 0 the two factors are not related If r < 0 as one factor increases, the other factor will decrease We must then evaluate whether the r value represents a true association between the variables or whether it is simply due to chance If the correlation coefficient is significant it indicates that there is a strong association between 2 variables Find the row for the correct degrees of freedom and determine whether the r value is significant at the 5% or 1% significance level If df – N – 2 5% chance that we could have gotten that r value due to random chance 1% chance that we could have gotten that r value due to random chance Significant association does not imply cause and effect Our value of 0.237 is not significant Correlation Between Variables Scatter plots: can be used to visualize the degree of correlation Correlation coefficient: measure of association between 2 variables r = 1 for perfect correlation r = 0 for no correlation

Habits of Mind & Quality of Character Curiosity Imagination & Creativity Skepticism Openness to New Ideas Honesty One must exercise limited skepticism Assumptions of science include: universe is real, senses are accurate, natural laws are knowable and consistent

Section 2: Statistics & Models Statistics is the practice of collecting and analyzing numerical data in large quantities Mean = average Distribution = relative arrangement of the members of a statistical population. It’s the ‘shape’ of the curve around the mean. Relative to the mean!

Human height has this type of distribution

The shape is determined by the mean and the standard deviation The shape is determined by the mean and the standard deviation. SD is the square root of variance. Look up the equation for variance

Probability—chance that an event will occur Below is a graph created after rolling 2 dice 100 times. What the chances that you would roll a 7?

Statistics in Everyday Life Examples Weather There’s a 50% chance of rain Climate Change The average global temperature has increased

Risk—probability of an unwanted outcome

Models—representations of objects or systems Physical Model—3D

Graphical Model—maps and charts

Conceptual Model

Section 3: Making Informed Decisions Decision Making Model Gather Info Consider Values Explore Consequences Make a Decision Evaluate the outcomes! ICED!

Case Study: Saving the Everglades Read the case study on pages 48 & 49 Answer questions 1 & 2