Fixpoint.test {ComparisonSurv} | R Documentation |

## Statistical inference methods for testing at a fixed time point

### Description

A function used to produce the results of various statistical inference methods for testing at a fixed time point.

### Usage

```
Fixpoint.test(time, status, group, t0)
```

### Arguments

`time` |
The follow up time for right censored data. |

`status` |
The status indicator, normally 1=event, 0=alive or right censored. |

`group` |
The group indicator for comparison, and the elements of this vector must take either 0 or 1. Normally, 0= control group, 1= treatment group. |

`t0` |
The fixed time point for testing. |

### Value

A list containing the following components:

`est.g0` |
The estimation of survival rates at the fixed timepoint for control group. |

`est.g1` |
The estimation of survival rates at the fixed timepoint for treatment group. |

`test` |
The results of statistical inference at the fixed timepoint. |

`method` |
Containing 5 types of statistical inference methods: naive, log, cloglog, arcsin, and logist. See more details in references. |

`t0` |
The prespecified fixed time point. |

`est` |
The survival rate at the prespecified timepoint. |

`lower.95.CI` |
The lower 95 percent pointwise confidence interval for the survival function. |

`upper.95.CI` |
The upper 95 percent pointwise confidence interval for the survival function. |

`statistic` |
The statistics of corresponding methods. |

`pvalue` |
The test P value of corresponding methods. |

### References

[1]Klein JP, Logan B, Harhoff M, et al. Analyzing survival curves at a fixed point in time. Statistics in Medicine, 2007, 26(24):4505-4519.

[2]Anderson JR, Pike LBC. Approximate Confidence Intervals for Probabilities of Survival and Quantiles in Life-Table Analysis. Biometrics, 1982, 38(2):407-416.

### Examples

```
#get 'Crossdata' from package
data(Crossdata)
data1<-Crossdata
#
#if there exist differences at 6 months and 12 months
Fixpoint.test(data1$time,data1$status,data1$group,t0=0.5)
Fixpoint.test(data1$time,data1$status,data1$group,t0=1)
```

*ComparisonSurv*version 1.1.1 Index]