item.stat: Item Statistics
In fsia: Import and Analysis of OMR Data from FormScanner

Description Usage Arguments Value Author(s) See Also Examples

This function computes some statistics for each item.

1	item.stat(obj, columns, weights = FALSE)

`obj`	An object containing the data imported by function `read.formscanner`, the key added by function `addkey` and/or weights added by function `addweights`.
`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.

A data frame with the following variables.

`item`	item label.
`score`	total score for each item. If `weights` is FALSE `score` is equal to the number of corrected responses.
`max`	maximum score for each item.
`perc`	ratio between score and max.

Michela Battauz

person.stat

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)