cell {bootstrap} | R Documentation |

## Cell Survival data

### Description

Data on cell survival under different radiation
doses.

### Usage

`data(cell)`

### Format

A data frame with 14 observations on the following 2 variables.

- dose
a numeric vector, unit rads/100

- log.surv
a numeric vector, (natural) logarithm of proportion

### Details

There are regression situations where the covariates are more naturally
considered
fixed rather than random. This cell survival data are an example. A
radiologist has run
an experiment involving 14 bacterial plates. The plates where exposed to
different
doses of radiation, and the proportion of surviving cells measured.
Greater doses lead to
smaller survival proportions, as would be expected. The investigator
expressed some
doubt as to the validity of observation 13.

So there is some interest as to the influence of observation 13 on the
conclusions.

Two different theoretical models as to radiation damage were available,
one predicting
a linear regresion,

`\mu_i = \mbox{E}(y_i \vert z_i) = \beta_1 z_i`

and the other predicting a quadratic regression,

`\mu_i = \mbox{E}(y_i \vert z_i) = \beta_1 z_i+\beta_2 z_i^2`

Hypothesis tests on `\beta_2`

is of interest.

### Source

Efron, B. and Tibshirani, R. (1993) An Introduction to the Bootstrap.
Chapman and Hall, New York, London.

### Examples

```
plot(cell[,2:1],pch=c(rep(1,12),17,1),
col=c(rep("black",12),"red", "black"),
cex=c(rep(1,12), 2, 1))
```

[Package

*bootstrap* version 2019.6

Index]