With the Texas Instruments TI-85, you can calculate the most commonly-used descriptive statistics for one variable (mean, standard deviation, sum of values, sum of the values-squared) and for regression/correlation between two variables (regression coefficient and intercept, correlation coefficient)
Data are entered and stored in a list (which allows
checking that you have entered correctly & keeps the numbers for recalculation)
For all statistical functions: Press STAT to see the statistics menu
There are three situations in which you enter data - one variable (actual data), one variable (with frequencies - grouped or ungrouped), two variable. Always clear old data before entering new data, or your results will be messed up:
Press STAT, press F2[EDIT] press ENTER, press ENTER
again (This accepts the names "xstat" and "ystat" for
the x & y variable lists - you can change them if you wish)(press F5
[CLRxy] to clear the data lists before entering new data)
Values go in as x- values (x1, x2 . . .) - the y1, y2 remain as 1's (enter
each value & press down arrow twice to jump to next x)
To change a value already typed in, use up/down arrow to highlight it, press
CLEAR, then enter new value
Press STAT, press F2[EDIT] press ENTER, press ENTER
again (This accepts the names "xstat" and "ystat" for
the x & y variable lists - you can change them if you wish)(press F5
[CLRxy] to clear the data lists before entering new data)
Values go in as x- values (x1, x2 . . .) - frequencies are entered as y
-( y1 is frequency of first value, etc.)(enter each value & press down
arrow )
Frequencies must be whole numbers (not decimals or fractions)
To change a value already typed in, use up/down arrow to highlight it, press
CLEAR, then enter new value
Press Press STAT, press F2[EDIT] press ENTER, press
ENTER again (This accepts the names "xstat" and "ystat"
for the x & y variable lists - you can change them if you wish)(press
F5 [CLRxy] to clear the data lists before entering new data)
Each pair goes in as an (x, y) pair: (x1, y1) then (x2, y2) etc.
If you just entered the data (looking at the xn
= yn = list) press 2nd F1 [CALC] (will see "xlistname = xStat"
at top of screen) ENTER, ENTER (accepting names) press F1 [1-VAR]
If you are on the "Home" screen (no menus showing), press STAT,
F1[CALC], ENTER, ENTER (accept names), then F1[1-VAR]Press 2nd-matrix [STAT],
1[1-var] then ENTER
You will see a screen with mean(x-bar), sum of x's , sum of x-squared's
( not "sum of squares" SS(x)) sample standard deviation (Sx) population
standard deviation [not much use] and sample size (n - the sum of the yi's)
If you just entered the data (looking at the xn
= yn = list) press 2nd F1 [CALC] (will see "Xlistname = xStat"
at top of screen) ENTER, ENTER (accepting names) press F2 [LINR]
From the "Home" screen, press STAT, F1[CALC], ENTER, ENTER (accept
names), press F2 [LINR]
You will see a screen which gives a (intercept) b (slope) and r (correlation
coefficient). [You might want to write on your calculator, or on the inside
of the cover, something like a=int, b=slope, because some people use a &
b the other way around]
Errors or questions? Please let me know: cpeltier@saintmarys.edu
Last update 7/20/98