Name: _________________________________________________________________ Period: ____ Organizing and Analyzing Data: (edited in red by Mr. Noble) Data tables: Data tables help organize your data, especially your quantitative measurements. Include a title with both the Manipulated variable (MV) and Responding Variables (RV), title the far left column of your table with the MV and list the levels below. The RV for each trial is titled in the columns to the right of the MV (include units) and your calculated value (like averages) are titled in the far right column. Example: Effects of different types of exercise on Heart Rate Heart Rate (beats / minute) Types of exercise Trial 1 Trial 2 Trial 3 Average At rest Walking 1 min. Walking 5 min. Running 1 min. Running 5 min. ***If you are collecting data in intervals of time, you can list the times in the far left column instead and have a data table for each level. Example: Position vs. time (constant speed) Position vs. time (accelerating) Time Position Time Position (seconds) (meters) (seconds) (meters) 0 seconds 0 seconds 5 seconds 5 seconds 10 seconds 10 seconds 15 seconds 15 seconds Analyzing Data: After data is collected, it needs to be analyzed to see if there are any trends or relationships in your variables. To help visualize trends in your quantitative data, you will make a graph and then include a statement which reflects any trends. Be sure to address all of your levels and cite specific data (numbers) to support your trend statement . Your cited data should cover the full range of your levels. A summary statement can also be made for your qualitative information. It is important that you do not use inferences in your trend statements. Graphs: They are used to help interpret and visualize any trends in your quantitative data. If your data is fairly consistent (reliable) between trials, the average would be a good representation of your trend to graph. If there are fluctuations in your trials, data for each trial should be included in the graph. There are different kinds of graphs and it is important to know which one to use. The manipulated variable almost always goes on the horizontal axis (x‐axis) and the responding variable almost always goes on the vertical axis (y‐axis). One exception is time; if time intervals are the responding variable, they are often recording on the X‐axis, because we are used to visualizing time passing from left to right. Bar graphs: Usually students’ favorite graph but usually not used in science. It is used when your responding variable is grouped into categories and is not necessarily related to each other and there is no expected trend that occurs between the categories. For example: Number of students in my classroom per period. Scatter Plot: This graph is very frequently used in science to show relationships between manipulated and responding variables. Even though the data points may be spread out, the relationship between the variables should be continuous (without gaps), and a “best‐fit” line or curve can be drawn to show the complete trend (sometimes called a “trend line”) For example: Height of a plant vs. the amount of water it was given. How to make a graph: 1. First, decide which type of graphs to use (line or bar). 2. Label your X and Y axis with a description and units. The Y axis is almost always your responding variable, and the X axis is your manipulated variable (except, for example the exception when the X axis is time). 3. Title your graph (Y axis variable vs. X axis variable). 4. Determine your increments of each variable. Look at your maximum values and make sure the graph will be big enough to include the data and interpret the trend it represents. Also, decide whether the origin, (0,0) needs to be included in the data (and on the graph) And, make sure the numbering is consistent (evenly spaced) on each of your axes. 5. Draw a best‐fit line or curve if appropriate. DO NOT connect the dots with line segments (as shown below) Example: Avg. Height (cm)
Average Height of a Bean Plant over 30 days vs. The amount of water given each day
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Amount of water given each day (mL)
Practice questions: 1. Indicate by writing the word “line” or “bar” indicating which type graph should be used for the following data sets: a. Favorite movie genre vs. gender ____________ b. The height a ball bounces vs. the brand of ball ___________ c. The height a ball bounces vs. the height it is dropped ______________ 2. Practice Data Tables and Graphs: On a separate sheet of paper (using graph paper or a computer is preferable) make a blank data table and graph for the following experiments. a. Measuring the audio volume (in decibels‐dB) of a guitar string as you increase the force (in Newtons ‐N) you use to pluck it. The force will be increased from 0N to 3N in increments of 0.5 Newtons. b. You are measuring the time it takes (in seconds‐ s) for an object to hit the ground from various heights (in meters‐m). The heights range from 0 meters to 5 meters (increments of 1 meter). c. You are measuring how far a car travels, in meters, over different increments of time (every 2 seconds for a total of 20 seconds).