# Summary of a balanced longitudinal data set

### Description

For a balanced longitudinal data set a vector of the mean response and variances at defined time points is returned along with the correlation matrix of the responses across the time points.

### Usage

1 | ```
summarybal(object, Y.col, times, use = "all.obs", na.rm, ...)
``` |

### Arguments

`object` |
a longitudinal data set in the balanced format. |

`Y.col` |
the column numbers of the longitudinal measurements at each design time point in the |

`times` |
a vector of unique time points of the longitudinal measurements. This does not have to be all of the study time points and may be a subset instead, but should match the columns defined in |

`use` |
an optional character string giving a method for computing
covariances in the presence of missing values. This must be (an
abbreviation of) one of the strings |

`na.rm` |
logical. Should missing values be removed? By default, |

`...` |
further arguments for the summary |

### Value

The function returns a `list`

with three elements: `mean.vect`

- a matrix with the time points in the first column and the mean response vector as the second column; `variance`

- the vector of variances for the response at the time points and `cor.mtx`

containing the correlation matrix of the responses between each pair of time points.

### Author(s)

Ines Sousa (isousa@math.uminho.pt)

### See Also

`to.balanced`

.

### Examples

1 2 |