Dr. Therese Shelton Some Notes on the TI83/84 family of calculators, especially for Probability and Mathematical Statistics

Download a "guidebook" (manual) at the TI site

Access a Named Distribution     The calculator has built-in functions for some of the named distributions. You can access them from the Catalog or through the DIST button.
2ND-DISTR, then cursor down to the desired entry. For example, cursor to A, below 0, for binompdf(
Alternatively, 2nd-CATALOG, then type the first letter of the distribution since you'll be in alpha mode, and cursor to the desired one. Example, type B, then scroll to binompdf( .     ENTER will paste this in. Then you can enter the required and optional parameters.
Distributions below: Normal, Student-t, Chi-Squared, F, Binomial, Poisson, Geometric
1: normalpdf(x [, μ, σ])
5: tpdf(x, df)
7: χ2pdf(x, df)
9: Fpdf(x, dfNum, dfDen)
y-value of the named continuous probability density function at the stated x-value. Use of the variable X is useful for graphing. Example: define Y1 = normalpdf(X), set the Window, and Graph.
2: normalcdf(x1, x2 [, μ, σ])
6: tcdf(x1, x2,df)
8: χ2cdf(x1, x2,df)
0: Fcdf(x1, x2, dfNum, dfDen)
Based on the named continuous cumulative distribution; yields the area under the named curve between x1 and x2.
3: invNorm(area [, μ, σ])
4: invT(area, df)
Calculates the x value associated with an area to the left of the x-value under the named pdf.
A: binompdf(n, p [, x])
C: poissonpdf(λ, x)
E: geometpdf(p, x)
y=value of the named discrete probability mass function. We can calculate a single value, create a table of values, or calculate lists of values. Each function is usually graphed as a histogram as described below. x can also be a list of values rather than a single value.
B: binomcdf(n, p [, x])
D: poissoncdf(λ, x)
F: geometcdf(p, x)
The named discrete cumulative distribution function; area under the named curve at and to the left of x. x can also be a list of values rather than a single value.
  • p must be a decimal between 0 and 1.
    σ and λ must be positive.
  • 1E99 is used to specify infinity.
    For normal distributions and some others, xmin=μ - 4 σ and xmax=μ + 4 σ gives a sufficient graphing interval.
  • There are other restrictions for certain distributions.
  • "x [, μ, σ]" means that x is required but that μ and σ are optional. That is, you can enter normalpdf(.35), in which case the default values of mean μ=0 and standard deviation σ=1 are used. Another example: normalpdf(50, 70, 8).
  • For the binomial pdf (or cdf), if no x is specified, the result is a list of all probabilities (or cumulative probabilities) across all x-values is returned.

Calculate and plot discrete probabilities     Example: binomial distribution with n=5, p=.2.     STAT/EDIT. Clear lists L1 and L2. In L1, enter {0, 1, 2, 3, 4, 5}. ursor up to the name L2. L2=binom(5, .2, L1)       ENTER.     continue to make a histogram from these lists.
If a distribution is not one that is built into the calculator, (like dice) treat it as data and enter it into the lists as described elsewhere.

Calculate some discrete probability values     Examples, Method 1: geometpdf(.2, {0,1,2,3,4}) .     binompdf(5, .2) .     binompdf(10, .3, {0, 2, 8}) .     Examples, Method 2: Y1 = binompdf(5, .2, X)     2nd-TBLSET     ENTER.
TbleStart = 0.     ENTER.     ΔTbl = 1     ENTER.     Indpnt:   Auto     ENTER.     Depend:   Auto     ENTER.     2nd-TABLE

Plot a named continuous distribution,     Example: normal distribution with &mu=70, &sigma=8. Y1 = normalpdf(X,70,8). graph. Adjust the window settings.

Statistical analysis on one variable     Enter the data into L1 (or another list).     STAT/CALC/1-Var Stats to paste this command into the home screen.     For each STAT CALC menu item, if neither Xlistname nor Ylistname is specified, then the default list names are L1 and L2. If you do not specify freqlist, then the default is 1 occurrence of each list element.
Note: Sx is the sample standard deviation; used for data. sx is the population standard deviation; used for probability. Remember that we use population statistics when we are certain that we have absolutely all of the data.     It is rare that we will need Sx, which is the sum of the data, or Sx2, which is the sum of the squares of the data.     For IQR, you will calculate Q3-Q1 (the calculator doesn't show it.)

Restore a list that no longer shows up on the Stat menu...     Stat/Edit     move the cursor onto the name, such as L3, where you wish to insert a list.     2nd-INS for insert; now you should see "Name=" at the bottom of the screen.     from here, 2nd-L1 works, or you can select a list name through 2nd-LIST/NAMES/ and scroll to the name.

Enter Data into a list     STAT/EDIT     In general, use L1 for x-values. If there are y-values, use L2.     I suggest you clear specified lists for each new problem: from the STAT LIST editor, cursor up onto a list name, and then press CLEAR (not DEL) and ENTER.     Then type the data.

Access values of calculated statistics (like the mean), so that the exact value can be used,     Enter data and calculate the appropriate statistics. (If you edit a list or change the type of analysis, all stat variables are cleared and will need to be re-calculated.)     VARS/5:Statistics, and select the appropriate menu.     For instance, here are some common statistics and the menu in which each is found.
XY Σ PTS
number of data points
mean
standard deviation
min
max
sum of x's
sum of squared x's
1st quartile
median
3rd quartile

Statistical plot types     Instructions for setting up other one-variable plots are similar to those for the histogram.     In order of appearance on the calculator:
scatter xyLine
(not used in Stat or Prob
histogram
"modified" box plot that shows outliers; the one we will use. boxplot that doesn't show outliers. do not use. normal probability plot. Typically select Y for the DataAxis setting.

Create a histogram     Enter the data into L1 (or another list). If you have just a list of values (like {70, 80, 70, 90}), you're finished entering data; in this case, enter "1" for "Freq" below. If, however, the data comes with counts (absolute frequencies) or probabilities (relative frequencies), then enter these into L2 (or another list); in this case, enter this list for "Freq" below.
Deselect all graphs and statistical plots. Make sure the graph mode is set to function.
Define the plot.
    2ND-[STAT PLOT] (above y=).
    cursor up to Plot1 (or whichever)     ENTER.
    cursor to "On"     ENTER
    cursor to "Type ="     cursor to the rightmost on the top row.     ENTER.
    cursor to "Data List:"     2ND-LIST     select list     ENTER
    cursor to "Data List:"     2ND-LIST     select list     ENTER
Set Freq to 1 or L2, as appropriate.
ZOOM/ZOOMSTAT after graphing for a reasonable amount of data.
If the histogram is unsatisfactory, change the window settings manually. Make sure that xmin and ymin are a bit smaller than the values, and xmax and ymax are a bit bigger, so that the histogram plots well. xscl controls the bin width, which in turn affects the number of bins.
TRACE to see the important values for each bin, especially to record your graph by hand on paper. Record the x-value cut offs for each bin. "n" is the frequency or relative frequency; indicate these on the y-axis.

Normal Distribution Areas     De-select all plots, including StatPlots.     Define the window settings for graphing. Remember that 4 standard deviations on either side of the mean shows practically all of a normal distribution; the y-values are between 0 and 1.
2nd-[DRAW]     DRAW     1:ClrDraw     ENTER. this clears any previous drawings. You MUST do this between each drawing (or you'll get wacky results.) Because these are "drawings" and not "graphs", the Graph button is useless; there's nothing in the y= menu or defined in a StatPlot to graph.
2nd-[DIST]     DRAW     1:ShadeNorm(     give the values for the lower value and upper value, then close with ) if this is for a standard normal. If, however, it is not a standard normal, then include the mean first, then the standard deviation; then close with ). Separate these values with commas.

Example: We want Prob{-0.5 < Z < 0.5} for a standard normal. Good window settings are Xmin=-4, Xmax=4, Xscl=1, Ymin=-0.2, Ymax=0.8, Yscl=0.2,Xres=1. 2ND-DISTR/(cursor down to A, below 0):binompdf(     ENTER. (or select binompdf( from the Catalog).
5, .2, L1)     ENTER. (This uses the values in L1 as the x-values.)
Set up a histogram but manually set xscl to 1.

Alternatively, use the table features.     Y1=    binompdf(    5,.2,     (hit the button "X,T,θ,n" to get the X)     2nd-TBLSET.     TblStart=0.     ΔTbl=1.     Indpnt: Auto.

Distribution Areas
Example: a Normal distribution.     De-select all plots, including StatPlots.
Define the window settings for graphing. Remember that 4 standard deviations on either side of the mean shows practically all of a normal distribution; the y-values are between 0 and 1.
2nd-[DRAW]     DRAW     1:ClrDraw     ENTER. this clears any previous drawings. You MUST do this between each drawing (or you'll get wacky results.) Because these are "drawings" and not "graphs", the Graph button is useless; there's nothing in the y= menu or defined in a StatPlot to graph.
2nd-[DIST]     DRAW     1:ShadeNorm(     give the values for the lower value and upper value, then close with ) if this is for a standard normal. If, however, it is not a standard normal, then include the mean first, then the standard deviation; then close with ). Separate these values with commas.

Example We want Prob{-0.5 < Z < 0.5} for a standard normal. Good window settings are Xmin=-4, Xmax=4, Xscl=1, Ymin=-0.2, Ymax=0.8, Yscl=0.2,Xres=1. 2nd-[DIST]     DRAW     1:ShadeNorm( -.5,.5)

Example We want Prob{55 < X < 62} for a normal distribution with mean 60 and standard deviation 7. 4 std devs from the mean yields 60 - 4*7 = 32, 60 + 4*7 = 88. Good window settings are Xmin=30, Xmax=90, Xscl=10, Ymin=-0.1, Ymax=0.1, Yscl=0.2,Xres=1. 2nd-[DIST]     DRAW     1:ShadeNorm(55,62,60,7)

TIP: If you have to fiddle with the window settings, 2nd-QUIT from the drawing, change the window settings, then 2nd-ENTRY     ENTER.

Creating a scatterplot without regression line     Enter the data into two lists.     Deselect all graphs and statistical plots. Make sure the graph mode is set to function.

Either do the following prior to graphing or use ZOOM/ZOOMSTAT after graphing. ZOOM/ZOOMSTAT adjusts the window settings to include all values.
Perform a "two variable statistics" to obtain the settings for the graphing window. Use the WINDOW button to change these settings.
    Use the min and the max of the x-data to set xmin and xmax on the graphing window.
    Use the min and the max of the y-data to set ymin and ymax on the graphing window.
Xlist and Ylist must be the same length.

Define the plot.
    2ND-[STAT PLOT] (above y=).
    cursor up to Plot1 (or whichever)     ENTER.
    cursor to "Type ="     (use the first one)
    cursor to "Xlist:"     2ND-LIST     select list     ENTER
    cursor to "Ylist:"     2ND-LIST     select list     ENTER
    GRAPH    

optional resizing: ZOOM     9:ZOOM/ZOOMSTAT; ENTER     (or manually change the window settings.)

Displaying the correlation coefficient     Do this only once. It will remain set unless you change batteries or have otherwise set DiagnosticOff. With DiagnosticOn, the correlation coefficient will also be shown when a regression is performed.
    2nd-CATALOG     press "D"     down arrow to "DiagnosticOn"     ENTER     ENTER

Linear Regression     Enter the data into two lists.
Clear Y1 if you wish to save the regression equation:     Y1=     CLEAR
Perform the regression
    STAT     cursor to CALC     "4:LinReg(ax+b)" or "8:LinReg(a+bx)" (do not choose "9:LnReg")
    2ND-LIST     select list     ENTER     , (comma)     select list    
    optional: to store equation
        , (comma)     VARS     cursor to Y-VARS     "1:Function"     cursor to the function desired     ENTER
    ENTER
Remember to turn off the plot of the regression line in the Y= menu prior to showing any other statistical plots.

Creating a scatterplot with regression line     make the scatterplot in PLOT1 as above. If regression seems appropriate, continue.
Perform the regression, but augment the commands stated above for a regression as follows.
    STAT     cursor to CALC     "8:LinReg(a+bx)"
    2ND-LIST     select list     ENTER     , (comma)     select list    
        , (comma)     VARS     cursor to Y-VARS     "1:Function"     ENTER to select Y1
    ENTER
Now GRAPH.

Find a confidence interval for 1-sample or 2-sample mean(s)
For means, either we have raw data or we have summary statistics. If we have data, enter it into a list or 2 lists, as is appropriate.
    STAT     TESTS     cursor down to the appropriate line; use 8 for a single mean, 0 for independent means.     ENTER.
(7 and 9 assume you know σ(s). You could choose that and enter the sample std dev value(s) for &sigma to approximate what we would do by hand if we use a z-distribution for large samples.)
If you have data for 1 mean or 2 means, choose "Data", select the list(s). If you have summary statistics, choose "Stats" and enter the values.
Enter the confidence level. For 2 means, choose "No" for Pooled (for our text.) "Calculate" and ENTER.
You will see the confidence interval. For a t-test, you will see df.

Perform a hypothesis test for 1-sample or 2-sample mean(s)
Either we have raw data or we have summary statistics. If we have data, enter it into a list or 2 lists, as is appropriate.
    STAT     TESTS     cursor down to the appropriate line; use 2 for a single mean, 4 for independent means with a t-distribution.     ENTER.
(1 and 3 assume you know σ(s). You could choose that and enter the sample std dev value(s) for &sigma to approximate what we would do by hand if we use a z-distribution for large samples.)
If you have data for 1 mean or 2 means, choose "Data", select the list(s). If you have summary statistics, choose "Stats" and enter the values.
Enter the hypothesized value. Select the appropriate alternative hypothesis. For 2 means, choose "No" for Pooled (for our text.) "Calculate" and ENTER.
You will see the value of the test statistic and the p-value. For a t-test, you will see df.
If you wish to see the shaded area beyond the test statistic value for the alternative hypothesis that you chose, STAT/TESTS/ etc. as before but select DRAW instead of calculate. This also shows the test statistic value and a rounded p-value.

Find a confidence interval for 1-sample or 2-sample proportion(s)
For means, either we have raw data or we have summary statistics. If we have data, enter it into a list or 2 lists, as is appropriate.
    STAT     TESTS     cursor down to the appropriate line; use 8 for a single mean, 0 for independent means; Cursor down to A for a single proportion, B for two proportions.     ENTER.
The "x" value(s) are the number of "successes". For instance, if our sample indicates that 25 out of 200 surveyed love chocolate, then the sample proportion, p-hat, is .00125, but "x" is 25. If you are given n and p-hat, then x is the product of n and p-hat.
Enter the confidence level. "Calculate" and ENTER.
You will see the confidence interval.

Perform a hypothesis test for 1-sample or 2-sample proportion(s)
Either we have raw data or we have summary statistics. If we have data, enter it into a list or 2 lists, as is appropriate.
    STAT     TESTS     cursor down to the appropriate line; use 5 for a single proportion, 6 for two proportions.     ENTER.
Enter the hypothesized value for a single proportion. Select the appropriate alternative hypothesis.
The "x" value(s) are the number of "successes". For instance, if our sample indicates that 25 out of 200 surveyed love chocolate, then the sample proportion, p-hat, is .00125, but "x" is 25. If you are given n and p-hat, then x is the product of n and p-hat.
"Calculate" and ENTER.
You will see the value of the test statistic and the p-value.
If you wish to see the shaded area beyond the test statistic value for the alternative hypothesis that you chose, STAT/TESTS/ etc. as before but select DRAW instead of calculate. This also shows the test statistic value and a rounded p-value.

Entering data into a matrix     We do this before performing a chi-square test.
    2nd-MATRIX     EDIT     choose the matrix name, such as [A].     ENTER    
type the number of rows;     ENTER     type the number of columns     ENTER. enter all of the values in the contingency table.

Perform a chi-square test     Enter the counts (absolute frequencies) of the table into a matrix, as above; it is easiest to use [A].
    STAT     cursor to TESTS     cursor down to "C: χ2-Test..."     ENTER.
(If you used matrix [A], just) cursor down to "Calculate" and ENTER. Expected values will be in Matrix [B].
See the p-value and the df.
If you wish to see the shaded area past the test statistic value, STAT/TESTS/"C: χ2-Test...", DRAW. This also shows the test statistic value and a rounded p-value.