Groundlearn / BA II Plus / Mean and standard deviation
BA II Plus mean and standard deviation: the DATA and STAT worksheets
Sample statistics on returns in Quantitative Methods.
The keys
| 2NDDATA2NDCLR WORK | Opens and clears the data worksheet. |
| valueENTER↓↓ | Each X0n; skip the Y0n line for one variable. |
| 2NDSTAT | Opens the statistics worksheet. |
| 2NDSETuntil 1-V | One-variable statistics. |
| ↓ | Scroll: n, x̄, Sx (sample) and σx (population). |
Worked example
Annual returns of 10%, −5% and 15%. Mean and sample standard deviation?
| 2NDDATA2NDCLR WORK | Clear. |
| 10ENTER↓↓ | X01 = 10. |
| 5+/−ENTER↓↓ | X02 = −5. |
| 15ENTER | X03 = 15. |
| 2NDSTAT↓↓↓ | n = 3, x̄ = 6.667, Sx = 10.408. |
The trap
Sx divides by n − 1 and σx by n. Exam questions on a sample of returns want Sx; σx here would be 8.498.
The terms behind it
- Standard deviationThe square root of variance, in the same units as the data.
- VarianceThe average squared deviation from the mean — the standard measure of dispersion.
More BA II Plus keystrokes
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- BA II Plus effective annual rate: the ICONV worksheetComparing quoted rates with different compounding, and EAR questions.
- BA II Plus loan amortization: interest and principal for any yearMortgage payments, interest and principal splits, and outstanding balances.
- BA II Plus bond price from yield: keystrokes and the semi-annual trapFixed income pricing at every level, using the TVM keys.
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