Using the Regressor
The "Regressor"is an interactive graph that calculates the slope of an isochron.That slope is related to the age of crystallization of an igneous rock or the age of metamorphism of a metamorphic rock. The equation that expresses the relationship between age and slope is that of a straight line: Y = mX + b. You are going to determine the value of the slope term, "m"
Use the slider controls next to the graph to adjust the slope and intercept of the "BEST FIT" isochron line so that the "errors" value is at a minimum. You will have to go back and forth between the slope and the intercept adjustment in order to minimize the errors number. The process of minimizing the "sum of the squares of errors" (the errors term) is called "Least Squares". You can use the slider arrows to change slope and intercept values or you can type numbers directly into the text fields, followed by pressing your return key.)
Depending on your browser type, the error term might be displayed in "Scientific Notation." Note that 2.21e-006 is GREATER THAN 9.11e-007. Close this Window when you are finished with it.