Texas Instruments TI-84 PLUS - Graphing Calculator - Statistical Variables

Chapter 12: Statistics 206
system displays the revised parameter value in the symbolic expression Y=mX+B, and refreshes
the graph with the updated Manual-Fit Line.
Select y 5 to finish the Manual Fit function. The calculator stores the current mX+b
expression into Y1 and makes that function active for graphing. You can also select Manual-Fit
while on the
Home screen. You can then enter a different Y-Var such as Y4 and then press Í.
This takes you to the Graph screen and then pastes the Manual-Fit equation in the specified
Y-Var.
In this example,
Y4.
Statistical Variables
The statistical variables are calculated and stored as indicated below. To access these variables
for use in expressions, press , and select
5:Statistics. Then select the VARS menu shown in
the column below under
VARS menu. If you edit a list or change the type of analysis, all statistical
variables are cleared.
Variables
1-Var
Stats
2-Var
Stats Other
VARS
menu
mean of x values
vv
XY
sum of x values
Gx Gx G
sum of x
2
values Gx
2
Gx
2
G
sample standard deviation of x Sx Sx XY
population standard deviation of x
sx sx
XY
number of data points n n XY
mean of y values
w
XY
sum of y values
Gy G
sum of y
2
values Gy
2
G
sample standard deviation of y Sy XY
population standard deviation of y
sy
XY
sum of x
… y Gxy G
minimum of x values minX minX XY
maximum of x values maxX maxX XY
minimum of y values minY XY
maximum of y values maxY XY
1st quartile Q1 PTS
median Med PTS
3rd quartile Q3 PTS
regression/fit coefficients a, b EQ
polynomial, Logistic, and SinReg
coefficients
a, b, c,
d, e
EQ