# Item Statistics

### Description

This function computes some statistics for each item.

### Usage

1 |

### Arguments

`obj` |
An object containing the data imported by function |

`columns` |
A vector containing which columns to use. Columns can be specified by name or number. |

`weights` |
Logical. If TRUE weights are used to compute the score. |

### Value

A data frame with the following variables.

`item` |
item label. |

`score` |
total score for each item. If |

`max` |
maximum score for each item. |

`perc` |
ratio between score and max. |

### Author(s)

Michela Battauz

### See Also

`person.stat`

### Examples

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | ```
data(test)
data(key)
data(weights)
data(weights_multiple)
testk <- addkey(test, keydata = key)
testw <- addweights(testk, weightsdata = weights)
testwm <- addweights(test, weightsdata = weights_multiple)
# number of correct responses for each item
ist <- item.stat(obj = testk, col = 2:41)
head(ist)
# sum of weights of correct responses for each item
ist <- item.stat(obj = testw, col = 2:41, weights = TRUE)
head(ist)
# sum of weights of every response for each item
ist <- item.stat(obj = testwm, col = 2:41, weights = TRUE)
head(ist)
``` |