LINEAR REGRESSION – a process used to find the equation of the line of best fit in a scatter plot.
1) Create a table/2 lists using your 2 sets of data (stat/enter)
2) Find your a and b values (stat/calc/linreg/enter/calculate/enter). Remember "a" represents the slope and" "b the y-intercept.
3) Plug in the values of a and b to find the linear equation (y = ax + b) modeled by the data
4) The "r" value represents the correlation coefficient. This is a measure of the strength and direction of the linear relationship between the equation above and the points/data set. The value is always between -1 and 1. (It is unrelated to the specific slope or y-intercept.)
QUADRATIC REGRESSION – a process used to find the equation of the parabola of best fit.
1) Create a table/2 lists using your 2 sets of data (stat/enter)
2) Find your a, b, and c values (stat/calc/quadreg/enter/calculate/enter)
3) Plug in the values of a, b, and c to find the quadratic equation (y = ax^2 + bx + c) modeled by the data.
4) The "r^2" value represents the coefficient of determination which is similar to the correlation coefficient. It is a measure of how closely an equation fits or models the data. The value is always between 0 and 1.
IMPORTANT NOTE: If r or r^2 does not appear when doing regression, go to catalog (2nd/0), scroll down, and press DiagnosticOn/enter
SOLVING SYSTEMS OF EQUATIONS USING MATRICES – a process used to find the values of the variables that satisfy each equation in the system:
1) Make sure all of the equations in the system are written in standard form
2) Put all equations into one augmented matrix, with each equation representing 1 row
3) Make sure to use 1 as the matrix entry if there is no coefficient in front of a variable and 0 as the matrix entry if a specific variable doesn’t appear in an equation **
4) Input the matrix into your calculator (2nd/matrix/edit/enter/dimensions***/enter #’s)
5) Find the solution (2nd/quit/2nd/matrix/math/rref***/enter/2nd/matrix/enter/”)”)
6) The final column represents the solution of the system. The first number is the value of the first variable, the second number is the value of the second variable, etc.
*rref means reduced row echelon form **use (-) for negative, not minus ***usually 2x3 or 3x4
SCIENTIFIC NOTATION:
See: https://nnlm.gov/sites/default/files/nto/files/TOXNET/whatdoesEmeancalculator.pdf