Texas Instruments TI-73VSC Guidebook - Page 143

Chapter 7: Statistical Analyses 137 Variables r r2 or R2 RegEQ x1,y1,x2,y2, x3,y3 a, b, c Definition Correlation coefficient Coefficient of determination Regression equation Summary points Regressionà fit coefficients VARS Menu EQ EQ EQ PTS EQ n (number of data points) n=number of x data points in a 1-Var Stats analysis or the number of x and y data points in a 2-Var Stats analysis. Since both variable lists always have the same number of list elements in 2-Var Stats, n for x is always equal to n for y. Therefore, n applies to both the x and y analyses. freq (Frequency Lists) If freq is specified, n is equal to the sum of the elements in that list. For example, if the freq is {2,2,3,1,2}, n={2+2+3+1+2}=10. Q1, Q3, and Med Q1, Q3, and Med are undefined if the freq contains non-integer values. They also are not calculated if the freq contains a value larger than 99. RegEQ The calculator stores the most recently generated regression equation (see - v CALC menu items 3–7) to the variable, RegEQ. If, for example, you execute 5: LinReg(ax+b), but you don’t initially store RegEQ to a Yn variable, you can later insert RegEQ into the Y= editor. The calculator graphs the regression equation when it is selected. If the frequency for an element or data pair is 0, the element or data pair is ignored in the calculation.