The Line of Best Fit CHAPTER 2 LESSON 3
Observed Values- Data collected from sources such as experiments or surveys Predicted (Expected) Values- Points predicted by the linear model Errors (Deviation)- The differences between observed and predicted values of the dependent variable Line of Best Fit- The line with the smallest value for the sum of the squares of the errors Method of Least Squares- The process of finding the line of best fit Interpolation- Estimating a value between known values of data Extrapolation- Estimating a value beyond known values of data Center of Gravity- The one point on the line of best fit that can be determined by hand without much trouble VOCABULARY
On your calculator Press the STAT button Press ENTER on option 1:Edit Fill out Tables L1 and L2 Press the STAT button Go to the CALC tab Option number 4: LinReg(ax+b) Select Calculate Press Enter CALCULATING THE LINE OF BEST FIT
LinReg Y=ax+b A= some # B= some # Round to 3 decimal places READING LINEAR REGRESSION
Press STAT Select Option 1: Edit.. Highlight L1 on top Hit clear, then enter Highlight L2 on top Hit clear, then enter CLEARING TABLES AFTER LINREG
The center of gravity is the one point on the linear regression line that can be calculated by hand To find the x coordinate of the center of gravity, find the mean of all the observed x values To find the y coordinate of the center of gravity, find the mean of all the observed y values CENTER OF GRAVITY
Observed value – Predicted value Observed value comes from the table given to you Predicted value comes from the regression equation FINDING ERROR IN DATA
EXAMPLE CwCn
CONTINUED Cw Observed CnPredicted CnErrorError 2
Worksheet 2-3 HOMEWORK