xmpl {prefmod} | R Documentation |
Data (Likert items): Example Data Set
Description
Data to illustrate the usage of patt.design for Likert items
.
Usage
data(xmpl)
Format
A data frame with 100 observations on the following 5 variables.
I1
- responses to first Likert item, (1) strong agreement, to
(5) strong disagreement
I2
- responses to second Likert item, like
I1
I3
- responses to third Likert item, like
I1
SEX
- (1) male, (2) female
EDU
- (1) low education, (2) high education
All values are numeric.
Details
Datasets and/or dataframes used in patt.design
are required
to have the follwing structure:
- All values must be numeric.
- The item responses must be in the leftmost columns (such as
I1
to I3
above).
- Categorical subject covariates follow the item responses (rightmost columns)
and their levels must be specified as consecutive integers. If in a used
datafile or dataframe these are defined as R factors they will be
converted to integers. This is not possible if characters are used
as factor levels and, consequently,
patt.design
will produce an error.
Examples
data(xmpl)
des<-patt.design(xmpl, nitems = 3, resptype = "rating",
cov.sel = "SEX")
head(des)
[Package
prefmod version 0.8-13
Index]