There are five parts to this discussion: Read, identify three different variable pairs, create table, create graph, describe in words.
Prepare: Prior to beginning work on this discussion, read Chapter 9: Modeling Our World and Chapter 10: Modeling with Geometry in your course text, especially pages 532-3 & 536-9.
For this discussion, identify three different variable pairs in which two quantities appear to be related from either recent news stories, the web, or that you encounter in your everyday life. Each variable pair should come from a different source (as illustrated in the week 4 Discussion Sample) and there should be three sets of paired variables total.
Important note: Only one of the variables can use “time” as an independent variable. For example, you cannot have your variable pairs be (time, dependent variable 1), (time, dependent variable 2) and (time, dependent variable 3). However, you can have your variable pairs be (time, dependent variable 1), (independent variable 2, dependent variable 2) and (independent variable 3, dependent variable 3).
For inspiration, use the examples listed in the solution to Example 1 on p. 537 of the text, or the Week 4 Discussion Sample download, MAT205.W4.DiscussionSample.pdf. Be sure to select different examples!
After you have identified three different variable pairs (from distinct sources), make a table of between 10 and 20 entries of data values for each of your variable pairs.
Then, graph your data values for each variable pair and describe in words the function that relates the variables. For each pair, write down at least five (5) points on the graph. Draw the graph using paper & pencil or use an online graphing calculator like Desmos Graphing Calculator (Links to an external site.).
Describe Your Results in Words
For each of the pairs you listed, identify the dependent and independent variables and briefly describe the relationship.
The Easy Way to Plot and Graph Points
Use the Desmos Graphing Calculator (Links to an external site.): (You need not create an account.)
Click on the “+” at the top left corner.
Select “table” from the drop-down menu.
Type in your points. If your point is (2, 30), then x1 is 2 and y1 is 30.
** If your points contain any values beyond ±10, click the minus sign in the upper right-hand corner a few times to zoom out so you can see the points. **
To add a line connecting the points:
Click and hold on the circle with four dots on it (next to y1). Click the circle next to “Lines” to show the connecting line. Your graph is done.
To share the graph, take a screenshot. [This site will show you how: http://www.take-a-screenshot.org/ (Links to an external site.). Click on the tab for Mac or Windows at the top, if needed.] Alternatively, click on the arrow in a box at the upper right hand corner of the screen, then you can “Export Image” as a .png file (it appears in your “Downloads” folder) and attach this to your discussion post or drop and drag into a Word file.