Chapter 7: Statistical Analyses 137
7307ENG.DOC CH 7, Statistical Analyses, English Julie Hewlett Revised: 07/29/98 12:07 PM Printed: 05/19/99
9:00 AM Page 137 of 22
Variables Definition VARS Menu
rCorrelation coefficient EQ
r2 or R2Coefficient of determination EQ
RegEQ Regression equation EQ
x1,y1,x2,y2,
x3,y3
Summary points PTS
a, b, c Regressionà fit coefficients 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.
Q
1
, Q
3
, 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.