Instant summary statistics from a list - no formulas to compute by hand.
In short: One-variable statistics gives the key summary values of a data set in a single step: the mean, standard deviation, median, quartiles, minimum and maximum. You enter the data in a list, with frequencies if it is grouped, run the one-variable analysis and read the results. Use it for any question about centre or spread.
| TI-84 Plus CE | Casio fx-CG50 and fx-CG100 | TI-Nspire CX | |
|---|---|---|---|
| Key sequence | STAT → Edit → type values into L1. Then STAT → CALC → 1:1-Var Stats, choose L1, Calculate. | Statistics menu → enter data in List 1 → CALC (F2) → 1-VAR. | Add a Lists & Spreadsheet page, name a column and enter data; then a Calculator page → menu → Statistics → Stat Calculations → One-Variable Statistics. |
Tip: Sx vs σx: use σx (population) for a complete data set, Sx (sample) for a sample. IB usually wants σx.
Tip: Sx vs σx: use σx (population) for a complete data set, Sx (sample) for a sample. IB usually wants σx.
Tip: Sx vs σx: use σx (population) for a complete data set, Sx (sample) for a sample. IB usually wants σx.
Here's a real IB-style question that uses exactly this technique.
The data set is 4, 5, 5, 6, 7, 8, 9, 10. Find the mean and the population standard deviation, each to 3 significant figures.
Instant summary statistics from a list - no formulas to compute by hand. A question gives a list or frequency table of data and asks for the mean, median or standard deviation. Comparing the spread (standard deviation) of two data sets, not just their averages.
1. Enter the data into a list. 2. STAT → Edit → type values into L1. Then STAT → CALC → 1:1-Var Stats, choose L1, Calculate. 3. Read x̄ (mean), Sx (sample sd) or σx (population sd), and the five-number summary (min, Q1, median, Q3, max). 4. For frequency data, put values in one list and frequencies in another and set the frequency list.
1. Enter the data into a list. 2. Statistics menu → enter data in List 1 → CALC (F2) → 1-VAR. 3. Read x̄ (mean), Sx (sample sd) or σx (population sd), and the five-number summary (min, Q1, median, Q3, max). 4. For frequency data, put values in one list and frequencies in another and set the frequency list.
1. Enter the data into a list. 2. Add a Lists & Spreadsheet page, name a column and enter data; then a Calculator page → menu → Statistics → Stat Calculations → One-Variable Statistics. 3. Read x̄ (mean), Sx (sample sd) or σx (population sd), and the five-number summary (min, Q1, median, Q3, max). 4. For frequency data, put values in one list and frequencies in another and set the frequency list.
Sx vs σx: use σx (population) for a complete data set, Sx (sample) for a sample. IB usually wants σx.
In the worked example on this page (3 marks, Paper 2), the marks are: M1: Enter the data as a one-variable list; A1: Mean = 6.75; A1: σ = 1.98.
Questions that need this technique link back to this guide. Try one in practice mode, or see every GDC guide.