1 / 15

Graphing with Computers

Graphing with Computers. Pressure and Density. What is Pressure?. Pressure = Force = lbs area in 2 Let me propose the following experiment. Pressure Experiment. A series of 1 lbs, 1 in 2 disks are placed on a scale. What would the data Look like?. Data From Experiment.

preston
Download Presentation

Graphing with Computers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Graphing with Computers Pressure and Density

  2. What is Pressure? Pressure = Force = lbs area in2 Let me propose the following experiment

  3. Pressure Experiment • A series of 1 lbs, 1 in2 disks are placed on a scale What would the data Look like?

  4. Data From Experiment

  5. This is a direct proportion. The pounds varies directly as the in2 We can use a “best fit” line to describe the relationship

  6. R2 = correlation coefficient This tells us how well the Line is described. Perfect correlation = 1 Best Fit Line I use excel to determine the equation for the line. y = 1.0 x What units does y represent? x? So the equation really is lbs = in2

  7. Best Fit Line • The line describes the ratio or proportion • The ratio is the slope or pounds / in2 • In the is example it is equal to 1 • This means for every pound added, one in2 is added • R2 = 1 tells us there is perfect correlation in our data • Our accuracy and precision are perfect • Our data was unrealistic • Let’s throw in some error and see what happens

  8. Data From Experiment

  9. Notice the data is not in perfect line. We can draw in a best fit line, but it is more accurate to let the computer do it

  10. Notice the slope is not perfectly 1 any more! The equation of y = mx +b turns into pounds = .9956 in2 + 0 R2 , our correlation coefficient is close to one. Good enough!

  11. Let’s Review • Plot the data. • Determine the type of proportion (direct) • Draw a best fit line • Determine the slope of the line • The slope is the relationship • It describes the proportion or ratio of the two variables

  12. Density • What are the units of density? g/mL • Given an unknown material • We can measure the grams • We can measure the mL by displacement • We can determine the density by using a graph!

  13. Graphing with Computers • Plot the data • Determine the type of proportion • linear or direct • Draw a best fit line • Also called doing a linear regression • Determine the slope of the line

  14. g/ml What are the units of the slope? What are the units of density? g/ml

  15. Let’s Switch to Excel • Use excel to graph and draw best line • Linear regressions are really easy !

More Related