1. Section 2.4 Representing Data

2. Graphing • Visual display of data • Picture demonstrating patterns

3. Circle Graph • Pie chart • Good for parts of a fixed whole • Percentages

4. Bar Graph • Shows quantity variations with factors • Independent variable  horizontal axis (x) • Dependent variable  vertical axis (y)

5. Line Graph • Most graphs in chemistry • Points on line represent intersection of data for two variables • Independent variable  x- axis • Dependent variable  y- axis

6. Best Fit Line • Best fit line  line drawn so that the same amount of points fall above and below it • Look at the slope of this

7. Slope • Steepness of a line • Rise over run • Change in y over the change in x y2 - y1=Δy x2 – x1Δx

8. Interpreting Slopes • Slope rises to the right= positive slope • Dependent variable increases as the independent variable increases

9. Slope sinks to the right= negative slope • Dependent variable decreases as the independent variable increases

10. Various Slopes

11. Interpreting Graphs • Identify independent and dependent variables • Look at measurement units and ranges • Determine linear or nonlinear relationship • Interpret the slope

12. Continuous Data • Points on line graph are connected • Interpolation: Reading areas between points • Extrapolation: Extend line beyond points