BrownMath.com → TI-83/84/89 → MATH200A Tech Notes
Updated 27 Dec 2015

# MATH200A Program — Technical Notes

Summary: This document contains the details of variable usage by the `MATH200A` program, and it’s probably of no interest to you unless you’re programming the TI-83/84 yourself. If you are, you should also look at MATH200Z Program — Technical Notes for technical details of the subprogram that is called by the `MATH200A` program.

If you just want to use the statistics utilities in the `MATH200A` program, please see MATH200A Program — Basic Statistics Utilities for TI-83/84.

Most parts of the `MATH200A` program leave useful results in variables, which you can use for further calculation. Use the [`ALPHA`] key. For instance, if you want a value from variable V, press [`ALPHA` `6` makes `V`]. Also, if you’re using any variables or statistics lists yourself, you don’t want to be surprised when the program changes their values. Below you’ll find complete information.

If you want to delete the lists to free up memory, press [`2nd` `+` makes `MEM`] [`2`] [`4`], scroll down to find each one, and press [`DEL`].

If you want to delete the single-letter variables, though it’s hardly worth the effort, press [`2nd` `+` makes `MEM`] [`2`] [`2`], cursor to each one, and press [`DEL`].

Program startup

• G = 1 if running on a high-resolution color screen (TI-84 Plus C or CE), 0 if running on a low-resolution black-and-white (TI-83+ or older TI-84), using a technique I learned in the forums at Cemetech

`1:Histograms etc` (calls MATH200Z with θ = 0)

• A = upper bound of highest class
• M = lower bound of lowest class
• N = number of data points
• W = class width
• LD = class midpoints
• LF = class frequencies
• used by program, not useful afterward: I, X, Y, θ

`2:Box-whisker` (calls MATH200Z with θ = 20)

• LA = first data list, if more than one sample
• LB = first frequency list, if more than one sample and first sample is a frequency distribution
• LC = second data list, if more than two samples
• LD = last data list
• LE = second frequency list, if more than two samples and second sample is a frequency distribution
• LF = last frequency list, if required
• used by program, not useful afterward: N, Y, θ
• N = number of trials
• P = probability of success on one trial
• X = number of successes “from”
• Y = number of successes “to”
• Z = probability (answer)
• N = sample size (number of data points)
• Z = critical value, unrounded
• system variable r ([`VARS`] [`5`] [`►`] [`►`] [`7`]) = correlation, unrounded
• LD = data list
• used by program, not useful afterward: X, Y, LF

`5:Sample size` (calls MATH200Z with θ = 100)

• C = confidence level (adjusted to >0, <1 if necessary)
• E = margin of error
• N = required sample size, a whole number
• P = prior estimate or 1
• Q = 0 or prior estimate 2
• S = standard deviation of population or sample
• Z = critical t(df,α/2) or z(α/2), unrounded
• used by program, not useful afterward: M, Str0 (deleted), Str1 (deleted), X, θ

`6:GoF test`

• C = χ² test statistic
• D = degrees of freedom (list length minus 1)
• P = p-value, unrounded
• X = number of expected values <5
• L3 = Expected numbers
• L4 = χ² contributions, (Observed−Expected)²/Expected
• used by program, not useful afterward: Y

`7:Two-way table`

• system variable df ([`VARS`] [`5`] [`◄`] [`◄`] [`6`]) = degrees of freedom
• system variable χ² ([`VARS`] [`5`] [`◄`] [`◄`] [`4`]) = χ² test statistic, unrounded
• system variable p ([`VARS`] [`5`] [`◄`] [`◄`] [`1`]) = p-value
• matrix [C] = χ² contributions, row and column totals, row and column percents; see MATH200A part 7 for details
• used by program, not useful afterward: X, θ, Y (deleted), Z (deleted), LC (deleted)