Data Presentation: Using graphs and tables

Why do we use graphs & tables? They make it easier to see comparisons. They make it easier to see changes. They organize data. Think about it! Is it easier to understand a paragraph of data, or to see it in a graph or table?

Data Tables Scientists use data tables to record data. Tables usually include more than one variable. Ex.: School enrollment diversity Ethnicity White (Caucasian) 68%65% African- American 23%22% Hispanic8%12% Other1%

Pie Charts or Circle Graphs These can be used to show parts of a whole. They are often used in surveys. Ex.: What’s your favorite movie genre? (asked 100 people)

Bar Graphs These are used to compare values. They are often used in studies or surveys that are repeated for different years or groups of people.

Line Graphs These graphs show how two variables interact. They are used most often to show change. The manipulated (independent) variable is on the x-axis, and the responding (dependent) variable is on the y-axis.

Variables A variable is something that can change, or vary, in an experiment. Independent variable: the thing you control in your experiment (always on x-axis) Dependent variable: the thing that changes as a result of controlling the independent variable, this is the thing you measure in an experiment (always on y-axis)

Other Words to Know Experimental group: the group that receives special treatment Control group: the groups that is used for comparison (kept “normal”) Constants: things that stay the same throughout the experiment for both control and experimental groups

What is the placebo effect? 20 people were asked to participate in a study investigating claims made by a new energy drink to increase energy levels by 50%. 10 people who had only gotten 5 hours of sleep were given the new energy drink, and then the other 10 who had also only gotten 5 hours of sleep received a drink they were told was the energy drink, but was actually carbonated sugar water. Of the 10 who received the energy drink, 7 reported feeling more awake than usual. Of the 10 who received the sugar water, 3 reported feeling more awake than usual. Why did these 3 feel this way? The placebo effect- or the power of mind over matter!