Module 26 of 47Lesson 1 of 13 · Core Statistics · Start here: meet your TI-Nspire CX II
Core Statistics · Start here
How to use these notes, and meet your TI-Nspire CX II
💻 Using the TI-Nspire CX Student Software on a laptop
- The screens in these notes are drawn exactly as the Student Software shows them. The keypad on the left of the software works like the handheld — click its keys with the mouse.
- menu: click menu on the on-screen keypad (or Documents Toolbox ▸ 🔧). The menu numbers and letters are the same as in these notes.
- enter = Enter · tab = Tab (next box) · esc = Esc · del = Backspace.
- Powers: type
^(Shift+6), the power, then press → to come back down before typing more. x² =^2then →. - Fraction: type
/· √: typesqrt(· π: typepi· eˣ: typeexp(· store: type:=. For EE (×10ⁿ) and i, click them on the keypad. - New page: Ctrl+I (or the Insert menu) · change page: Ctrl+← / Ctrl+→ · graph entry line: Ctrl+G · var: Ctrl+L.
- Radian / Degree: click Settings in the status bar at the bottom of the window. The mode (RAD or DEG) shows in the top bar.
- IB exam mode (Press-to-Test): everything in these notes works on the non-CAS TI-Nspire with the IB exam settings. In exam mode there are no dot-product, cross-product, unit-vector or eigenvalue keys and no Diff Eq graphs — the notes show the allowed way (type the components, use polyRoots on the characteristic equation, do Euler steps on a Calculator page).
- If you type
nDeriv(, the software shows it ascentralDiff(— it is the same command.
Statistics is about collecting, organising and understanding data. You use it every day without noticing: “On average I sleep 7 hours”, “Most of my class walk to school”, “The taxi is usually late”. In IB Maths AI, statistics is one of the biggest topics in both papers, and almost every statistics question is answered with the help of your calculator.
Every lesson follows the same pattern
1 · The big idea in simple words
We start from zero, with everyday examples. No previous knowledge needed.
2 · Key points
The facts and rules from the IB syllabus that you must know.
3 · Five worked examples
Easy → harder. Each one shows what to think and exactly which buttons to press on the TI-Nspire CX II.
4 · Two challenge questions
Exam-style: one Paper 1 style (short) and one Paper 2 style (longer, several parts). Try them first, then open the solution.
Prof. Kitso says
Each lesson also has a 🧪 Try it yourself activity. Type in your own numbers or drag points around and watch the answers change. Then do the same on your real calculator and check that you get the same numbers.
Reading the calculator instructions
Keys on the calculator look like this: menu💻 click menu on keypad enter ↵💻 Enter ctrl💻 Ctrl doc ▾💻 File menu tab💻 Tab home💻 click ⌂ on keypad. A path through the menus looks like this:
menu💻 click menu on keypad▸6: Statistics▸1: Stat Calculations▸1: One-Variable Statistics
It means: press menu💻 click menu on keypad, choose 6: Statistics, then 1: Stat Calculations, then 1: One-Variable Statistics. You can press the number key, or move with the touchpad and press enter ↵💻 Enter.
⚠️ About the screen pictures
The calculator screens in these notes are drawn to look like the TI-Nspire CX II, using the real menu names. Your screen may look slightly different (colours, number of decimal places, or the order you created pages in), but the numbers will be the same. When there are several screens, press ▶ Walk me through it to go one step at a time.
✍️ Exam habits from day one
- Give answers to 3 significant figures unless the question says otherwise (e.g. 3.979… → 3.98).
- Write down what you put into the calculator, e.g. “σx = 3.98 (from GDC)”.
- Always include units and answer in context (“the mean mass is 66.4 g”).
Meet your TI-Nspire CX II: five moves
Your calculator does the heavy arithmetic. Your job is to put the data in correctly, choose the right command, and read the right number. Every example in these notes uses these same five moves.
Move 1 · Start a new document and add a Lists & Spreadsheet page
- Press ⌂ on💻 click ⌂ on keypad. Choose 1: New (if asked to save the old document, choose No).
- A list of page types appears. Choose 4: Add Lists & Spreadsheet.
Home screen: press ⌂ on💻 click ⌂ on keypad, then 1: New Choose 4: Add Lists & Spreadsheet
Move 2 · Name your list and type the data
A list is a column of numbers with a name. Naming it lets you use it later on any page.
- Use the touchpad to go to the very top cell of column A (next to the letter A).
- Type a short name, e.g.
score, and press enter ↵💻 Enter. (Do not use names like “x” or “sum”: they are reserved.) - Move down to row 1 and type each number, pressing enter ↵💻 Enter after each one.
Empty spreadsheet: the top cell of A is for the NAME Column named score, data typed in
Move 3 · Add a Calculator page and run One-Variable Statistics
- Press ctrl💻 Ctrl doc ▾💻 File menu then 1 (Add Calculator). You are now on page 1.2.
- Go to menu💻 click menu on keypad▸6: Statistics▸1: Stat Calculations▸1: One-Variable Statistics and press enter ↵💻 Enter.
- Num of Lists: leave it as 1 and press enter ↵💻 Enter.
- X1 List: open the drop-down and choose
score. Frequency List: leave it as 1 if every value appears once. Press enter ↵💻 Enter.menu💻 click menu on keypad ▸ 6 ▸ 1 ▸ 1 X1 List = score, Frequency List = 1
Move 4 · Read the results
| Symbol on screen | Meaning | Used for |
|---|---|---|
| x̄ | mean | average |
| Σx | sum of all values | totals |
| σx := σnx | standard deviation (IB uses this one) | spread |
| sx := sn-1x | sample standard deviation (not used in AI SL exams) | ignore it |
| n | number of values | check you typed them all |
| MinX, MaxX | smallest and largest value | range |
| Q₁X, MedianX, Q₃X | lower quartile, median, upper quartile | IQR, box plots |
⚠️ The most common calculator mistake in IB statistics
There are TWO standard deviations on the screen. For IB Maths AI always use σx (the Greek letter sigma). The value sx is slightly bigger and will lose you the mark.
Move 5 · Draw a diagram with Data & Statistics
- Press ctrl💻 Ctrl doc ▾💻 File menu then 5 (Add Data & Statistics).
- Click “Click to add variable” under the x-axis and choose your list (e.g.
score). A dot plot appears. - Change the type with menu💻 click menu on keypad ▸ 1: Plot Type: choose Box Plot, Histogram, Scatter Plot, and so on.
Data & Statistics: menu💻 click menu on keypad ▸ 1: Plot Type Choose score on the x-axis, then pick a plot type
💡 Useful shortcuts
- Got a fraction like
instead of a decimal? Press ctrl💻 Ctrl enter ↵💻 Enter instead of enter ↵💻 Enter to get ≈ 13.3333. - Move between pages: ctrl💻 Ctrl + ◀ or ▶ on the touchpad.
- Undo a mistake: ctrl💻 Ctrl esc💻 Esc.
- Clear the Calculator history: menu💻 click menu on keypad ▸ Actions ▸ Clear History.
- Sort a list (to find the mode or median by hand): on the spreadsheet, select the column letter, then menu💻 click menu on keypad ▸ Actions ▸ Sort.
🧪 Try it yourselfYour own One-Variable Statistics screen
Type any list of numbers. The panel on the right shows what your calculator should show. Put the same numbers into your TI-Nspire (Moves 1–4) and check they match. Look for σx, not sx!
Next: Lesson 1 · Populations, samples & types of data