# Bone density

### Description

Relative spinal bone mineral density measurements on 261 North American adolescents. Each value is the difference in mineral density taken on two consecutive visits, divided by the average. The age is the average age over the two visits.

### Usage

1 | ```
data("bones")
``` |

### Format

General format `"Format1"`

(see `formatFuncy`

): A matrix of dimension 261x3.

### Source

http://statweb.stanford.edu/~tibs/ElemStatLearn/

### References

Hastie, Tibshirani and Friedman. The Elements of Statistical Learning (2nd edition) (2009). Springer-Verlag. 763 pages.

Gareth M. James and Trevor J. Hastie. Functional Linear Discriminant Analysis for Irregularly Sampled Curves. Journal of the Royal Statistical Society Series B. 63. 533–550. 2001

Gareth M. James and Catherine A. Sugar. Clustering for Sparsely Sampled Functional Data . Journal of the American Statistical Assocation. 98. 397–408. 2003