Bias and Collecting Data
The initial component of analyzing data is determining what information you would like to gather. When deciding on the type of data to collect, you should consider several factors. Among the many factors one must consider is whether the two variables are actually related. While scatter plots can be used to test relatedness, they are actually more useful as indicators of how two variables are related.
The way in which you plan to collect data must also be considered. Where will the data come from? Experimentation? Survey? Who or what should be included in the collection process? How should the data be measured?
Ironing out how you choose to sample data is perhaps the most crucial element of collecting data if you want to create unbiased results. If you look at the correlation between pollution levels in cities and population happiness, you wouldn't want to include people who don't live in the city in your sample. You also want to standardize answers. How can you measure a person's level of happiness? You should also consider the manner in which you choose to word questions if collecting information via a survey. It is important to create non-suggestive questions; that is, create questions that don't hint at a specific answer. Designing an experiment or survey in an attempt to obtain specific results will most likely do just that. Unfortunately, these data may not reflect the actual relationship between two variables.
Creating Scatter Plots
Scatter plots are simple graphs that represent a relationship between two variables. The independent variable is graphed on the x-axis, while the dependent variable is graphed on the y-axis. A proper scatter plot should include a title, labeled axes, and appropriate scaling. The title should be short, but descriptive. Once the scatter plot is set up, use the x- and y-coordinates of the ordered pairs to plot points.
Plotting points follows a simple procedure. The first coordinate of an ordered pair represents the x-coordinate and indicates how far to move from the origin along the x-axis. The second coordinate in the ordered pair represents the y-coordinate and indicates how far to move from the origin along the y-axis. If we were to sketch a vertical line from the x-axis and a horizontal line from the y-axis, we would plot a single point where these two lines intersect. Scatter plots are comprised of several points. In general, the more points, the more representative the data.
Interpreting Correlation and Bias
Correlation refers to the interdependence of two variables and is perhaps one of the most common initial forms of data analysis. After any set of data has been collected and organized, an analyst almost immediately checks to see if a correlation exists between the variables. The type of correlation depends on how the data (points) are scattered (or clustered). There are five types of correlation: strong positive, strong negative, weak positive, weak negative, and no correlation.
A strong correlation indicates that the data are tightly clustered and follow a specific trend or pattern. A weak correlation indicates that the data are scattered with only a slight visible pattern. Conversely, no correlation is indicated by a clear lack of pattern in the data. As stated earlier, correlation indicates whether a relationship exists between two variables. Correlation does not, however, indicate causation.
When interpreting the correlation of a set of data, it is important to consider several factors, such as whether the variables have extraneous connections not considered during the data collection process or whether the data were collected using a method that could potentially alter or affect the results in a specific manner.
Renewable and Nonrenewable Resources
Energy is one of the most frequently discussed and debated topics in the media today. With an ever growing population and a dwindling supply of fossil fuels, the public has begun looking toward more sustainable forms of energy.
Resources can be classified as either renewable or nonrenewable. Renewable resources are those that can be replenished naturally if once alive or biochemically if nonliving. Examples of renewables include resources like trees, which can be replanted or regrown if cut down or if it dies. Nonrenewable resources are those sources that cannot be replenished via natural processes, such as most of our primary energy sources like coal, natural gas, and oil.
1
These energy sources took millions of years to be converted from organic matter to fossil fuels. The move toward more sustainable resources has stemmed from a decrease in fossil fuel reserves, an increase in environmental awareness (a socio-political obligation to future generations), and increasing prices of resources such as petroleum.
Background Information on Carbon and the Greenhouse Effect
Carbon is the building block of organic life. It also serves as an energy source. Energy is found in many forms and transferred in a variety of ways through the carbon cycle. In fact, carbon is transferred using four processes: biological, geochemical, mixed biogeochemical processes, and human activities.
2
Vegetation absorbs carbon from the atmosphere, which can then be used as biofuels. In addition, plants use carbon dioxide to fuel photosynthesis to create carbohydrates, which are then consumed by humans and other animals. These carbohydrates are transferred throughout the food chain as a source of energy. Animals then release carbon in a variety of manners. Besides respiration, carbon that breaks down from dead plants and animals enters the soil and after millions of years and lots of pressure becomes a source of fossil fuels.
2
Geochemical processes include volcanic activity and erosion that release carbon either into the atmosphere or introduce it into the ocean. Human activities like burning fossil fuels (power plants, automobiles, etc.) and forests releases carbon back into the atmosphere in the form of carbon dioxide.
1
The greenhouse effect is one of the most well known environmental issues today. Normally, a percentage of light and heat from the sun enters the atmosphere while another percentage is reflected back into space.
3
The greenhouse effect essentially results in a higher percentage of heat being captured in Earth's atmosphere by greenhouse gases such as carbon dioxide, water vapor, methane, and nitrous oxide. This capture then results in warmer average temperatures, which impacts precipitation patterns, storm severity, and sea levels.
3
It is particularly important for Americans to understand the greenhouse effect, as carbon dioxide is a byproduct of fossil fuels and since about 98% of American carbon emissions stem from fossil fuel usage. In fact, about 85% of American energy comes from fossil fuels. In 2004, the United States was responsible for almost 22% of worldwide carbon emissions.
3
As the largest economy in the world, Americans have a responsibility for the earth. With the help of the current administration, scientific advancements and environmentalists, the U.S. is expected to lower its carbon impact by 36% by 2030. Of course, this will greatly depend on continued support by the American public.
3
Background Information on Energy Reserves
Fossil fuels are a type of nonrenewable energy. While deposits were created naturally, they took millions of years under high pressure to be converted from organic matter to something usable as energy. Once our fossil fuel reserves have been used up, we will no longer be able to rely on fossil fuels as a primary resource. Thus, monitoring our fossil fuel reserves is crucial (fossil fuel reserves refers to the remaining amount of a particular type of fossil fuel that can be mined given current deposits
4
). Refer to the appendix to see a table of coal reserves. This information can be used in Lesson 4 for the public service announcement project.
A Change in Public Opinion on Climate Change
The driving force behind any kind of social change is the extent to which the public perceives a need for change. Several polling agencies (Gallup and Pew Research) poll the public on a regular basis to gauge the public opinion on several matters. Climate change is one such topic and the newest results are concerning. "Belief that global warming is occurring had declined from 71 percent in April of 2008 to 56 percent in October -- an astonishing drop in just 18 months. The belief that global warming is human-caused declined from 47 percent to 36 percent."
5
Public Service Announcements
Public service announcements are a type of advertisement meant to raise awareness about an issue, impact public opinion about said issue, and possibly prompt social action. PSAs can be a powerful tool in manipulating public opinion, and are often used to reiterate the importance of creating social change when public focus wanes.
6
