This function is built into the main BAMSAUR functions and can be used to calculate the prediction and confidence intervals for individual age-at-death estimates
Interval(wear, wear.data, interval, level, df, s)
| wear | The average wear score from an individual, or a vector containing multiple scores. |
|---|---|
| wear.data | A vector containing all the average wear scores from the sample used to create the age-at-death estimation equation. |
| interval | The type of interval required. Can be "prediction" or "confidence". |
| level | The level of the prediction or confidence interval. A number between 0 and 1 (not inclusive). |
| df | The residual degrees of freedom from the regression analysis. |
| s | Standard deviation of the fitted regression line. |
returns the age range (+- years) of the estimated age(s)-at-death.
Calculation of age intervals is conducted using the formulas for the "confidence interval for the mean value of y for a given value of x", and "the prediction interval for an individual" (Altman and Garner 2000: 76-79)
Altman, D.G. and Gardner, M.J. (2000). Regression and correlation. In (eds) Altman, D. G., Machin, D., Bryant, T.N., and Gardner, M.J. (73-92). Statistics with Confidence(2nd ed.). BMJ Books.