1. Graphing Data

2. 3 Types of Graphs Bar Graph Line Graph Circle (or Pie) Graph

3. Bar Graph Useful for graphing items with different categories

4. Bar Graph I can change the order.

5. Bar Graph Does this change the information?

6. Bar Graph Whatever helps me get the point across

7. Circle Graph Ideal for showing percentages (fractions) All the parts add up to a whole

8. To find the percentage Divide the number in whichever category by the total number. – 10 students are too hot – 12 students are too cold – 2 students arent sure – 1 Teacher thinks it is just right The total is 25

9. To find the percentage 10/25 = 40% are too hot 12/25 = 48% are too cold 2/25 = 8% arent sure 1/25 = 4% is just right When making the graph: – 1 circle is 360° = 100% – Each percent is 3.6°

10. Line graph A line graph is useful when a dependent variable changes due to a relationship with an independent variable. The independent variable is x The dependent variable is y

11. Line graph Well start with an experiment.

12. Line graph As we turn the knob, we will take data. The knob location will be x, and the gauge reading will be y. – x=½ and y=0 – x=1 and y=1 – x=2 and y=3 – …and so on

13. Lets look at our data Lets make a table with our data. It may be helpful to sort the data by the independent variable. XY ½0 11 23 0 -3 XY -3 0 ½0 11 23

14. Lets look at our solutions Now lets plot the solutions on a graph. XY -3 0 ½0 11 23

15. Tow the line! It is reasonable to use the line as the solution rather than just the points. – Interpolation – Extrapolation

16. If it doesnt fit… Usually, real data doesnt fit on a perfect line. DO NOT play connect the dots. Make a regression line, or best fit line. WRONG

17. If it doesnt fit… Usually, real data doesnt fit on a perfect line. DO NOT play connect the dots. Make a regression line, or best fit line. – Eyeball it – Use Excel

18. It doesnt look square! We wont always have a straight line on a graph. This is a parabola. It is common in science graphs.

19. It doesnt look like anything! Often, we can write an equation for a graph. Sometimes we cant. Thats okay.

20. Assignment p. 26, 1-5 Worksheet Chapter 1 Test Friday 8/27 Bring Index Cards tomorrow