Type: | Package |
Title: | Single-Case Randomization Tests |
Version: | 1.3.1 |
Date: | 2019-12-20 |
Depends: | R (≥ 2.14.1) |
Imports: | graphics, utils |
Author: | Isis Bulte, Tamal Kumar De, Patrick Onghena |
Maintainer: | Tamal Kumar De <tamalkumar.de@kuleuven.be> |
Description: | Design single-case phase, alternation and multiple-baseline experiments, and conduct randomization tests on data gathered by means of such designs, as discussed in Bulte and Onghena (2013) <doi:10.22237/jmasm/1383280020>. |
License: | GPL-2 | GPL-3 [expanded from: GPL (≥ 2)] |
Repository: | CRAN |
NeedsCompilation: | no |
Packaged: | 2019-12-20 19:35:50 UTC; Tamal |
Date/Publication: | 2020-01-09 05:40:08 UTC |
Single-Case Randomization Tests
Description
Design single-case phase, alternation and multiple-baseline experiments, and conduct randomization tests on data gathered by means of such designs.
Details
Package: | SCRT |
Type: | Package |
Version: | 1.3.1 |
Date: | 2019-12-20 |
License: | GPL version 2 or newer |
Author(s)
Isis Bulte, Tamal Kumar De, Patrick Onghena
Maintainer: Tamal Kumar De <tamalkumar.de@kuleuven.be>
Hypothetical ABAB data
Description
Hypothetical data from Onghena (1992), collected in an ABAB design with 24 measurement times.
Usage
data(ABAB)
Format
A data frame with 24 observations.
The first column contains the condition/phase labels ("A1", "B1", "A2", "B2").
The second column contains the obtained scores.
The rows and columns are not labeled.
Source
Onghena, P. (1992). Randomization tests for extensions and variations of AB single-case experimental designs: A rejoinder. Behavioral Assessment, 14, 153-171.
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Examples
data(ABAB)
All assignments possibilities
Description
All assignment possibilities for the specified design are enumerated.
Usage
assignments(design, save = "no", MT, limit,
starts = file.choose(new = FALSE), assignments = file.choose(new = FALSE))
Arguments
design |
Type of single-case design: |
save |
Save the possible assignments to a file ( |
MT |
Measurement times: number of observations. |
limit |
For phase designs: minimum number of observations per phase. For alternating treatments designs: maximum number of consecutive administrations of the same condition. |
starts |
Only for multiple baseline designs: location of the file where the possible start points can be found. Default: a window pops up in which the file can be selected. |
assignments |
Only for user specified designs: location of the file where all the possible assignments can be found. Default: a window pops up in which the file can be selected. |
Details
When choosing to save the possible assignments to a file, a window will pop up (for multiple baseline designs or user specified designs this is the second pop-up window!!!) to ask where to save them. This location can be an existing file, as well as a new file that can be created by giving a file name and the extension .txt. In this latter case a confirmation is required ("The file does not exist yet. Create the file?").
For multiple baseline designs, when using the default starts
argument, first a window pops up in which is asked in what file the possible start points can be found. In this startpoint file, each row should contain all possibilities for one unit, separated by a tab. The rows and columns should not be labeled.
For user specified designs, when using the default assignments
argument, first a window pops up in which is asked in what file all the possible assignments can be found. In this file, each row should contain the sequence of conditions in one possible assignment, separated by a tab. There should be one row for every possible assignment. The rows and columns should not be labeled.
For multiple baseline designs, the possible combinations of start points for each unit are returned. There may be duplicates among these assignments if there are overlaps between the start points for different subjects, this is a result of the subjects also being randomized to the set of start points.
For all other designs, the possible sequences of conditions are returned (e.g., "A" "A" "A" "A" "B" "B" "B").
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Bulte, I., & Onghena, P. (2009). Randomization tests for multiple baseline designs: An extension of the SCRT-R package. Behavior Research Methods, 41, 477-485.
http://ppw.kuleuven.be/home/english/research/mesrg
See Also
quantity
to calculate the number of assignment possibilities.
selectdesign
to randomly select one of the assignment possibilities.
Examples
assignments(design = "ABAB", save = "no", MT = 24, limit = 4)
Nonexhaustive randomization distribution
Description
The nonexhaustive randomization distribution is generated by a random sample of all assignment possibilities.
Usage
distribution.random(design, statistic, save = "no",
number, limit, data = read.table(file.choose(new = FALSE)),
starts = file.choose(new = FALSE), assignments = file.choose(new = FALSE))
Arguments
design |
Type of single-case design: |
statistic |
Test statistic. For alternation designs, multiple-baseline designs and AB phase designs, there are 3 built-in possibilities: |
save |
Save the randomization distribution to a file ( |
number |
Number of randomizations required. Please note that the observed test statistic is always included in the randomization distribution. |
limit |
For phase designs: minimum number of observations per phase. For alternating treatments designs: maximum number of consecutive administrations of the same condition. |
data |
File in which the data can be found. Default: a window pops up in which the file can be selected. |
starts |
Only for multiple baseline designs: location of the file where the possible start points can be found. Default: a window pops up in which the file can be selected. |
assignments |
Only for user specified designs: location of the file where all the possible assignments can be found. Default: a window pops up in which the file can be selected. |
Details
When using the default data
argument, a window will pop up to ask in what file the data can be found. This text file containing the data should consist of two columns for single-case phase and alternation designs: the first with the condition labels and the second with the obtained scores.
For multiple-baseline designs it should consist of these two columns for EACH unit. This way, each row represents one measurement occasion. It is important not to label the rows or columns.
For multiple baseline designs, when using the default starts
argument, second a window pops up in which is asked in what file the possible start points can be found. In this startpoint file, each row should contain all possibilities for one unit, separated by a tab. The rows and columns should not be labeled.
For user specified designs, when using the default assignments
argument, second a window pops up in which is asked in what file all the possible assignments can be found. In this file, each row should contain the sequence of conditions in one possible assignment, separated by a tab. There should be one row for every possible assignment. The rows and columns should not be labeled.
Missing data should be indicated as NA
. When there is missing data, randomization distribution is generated as usual, but instead of randomly reshuffling numerical scores only, the missing data markers (NA
) are also included in the reshuffling. For test statistic calculations, missing data are omitted.
When choosing to save the randomization distribution to a file, next a window will pop up (for multiple baseline designs or user specified designs this is the third pop-up window, for all other designs it is the second window) to ask where to save it. This location can be an existing file, as well as a new file that can be created by giving a file name and the extension .txt. In this latter case a confirmation is required ("The file does not exist yet. Create the file?").
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Bulte, I., & Onghena, P. (2009). Randomization tests for multiple baseline designs: An extension of the SCRT-R package. Behavior Research Methods, 41, 477-485.
Edgington, E.S., & Onghena, P. (2007). Randomization Tests (4th ed.). Boca Raton, FL: Chapman & Hall/CRC.
Hope, A.C.A. (1968). A simplified Monte Carlo significance test procedure. Journal of the Royal Statistical Society, Series B 30, 582-598.
Onghena, P. & May, R.B. (1995). Pitfalls in computing and interpreting randomization test p values: A commentary on Chen and Dunlap. Behavior Research Methods, Instruments, & Computers, 27, 408-411.
http://ppw.kuleuven.be/home/english/research/mesrg
See Also
pvalue.random
to obtain the corresponding p-value for the nonexhaustive randomization distribution.
observed
to calculate the observed test statistic.
distribution.systematic
to generate the exhaustive randomization distribution and
pvalue.systematic
to obtain the corresponding p-value.
Examples
data(ABAB)
distribution.random(design = "ABAB", statistic = "PA-PB", save = "no",
number = 100, limit = 4, data = ABAB)
Exhaustive randomization distribution
Description
The exhaustive randomization distribution is generated by a complete enumeration of all assignment possibilities.
Usage
distribution.systematic(design, statistic, save = "no",
limit, data = read.table(file.choose(new = FALSE)),
starts = file.choose(new = FALSE), assignments = file.choose(new = FALSE))
Arguments
design |
Type of single-case design: |
statistic |
Test statistic. For alternation designs, multiple-baseline designs and AB phase designs, there are 3 built-in possibilities: |
save |
Save the randomization distribution to a file ( |
limit |
For phase designs: minimum number of observations per phase. For alternating treatments designs: maximum number of consecutive administrations of the same condition. |
data |
File in which the data can be found. Default: a window pops up in which the file can be selected. |
starts |
Only for multiple baseline designs: location of the file where the possible start points can be found. Default: a window pops up in which the file can be selected. |
assignments |
Only for user specified designs: location of the file where all the possible assignments can be found. Default: a window pops up in which the file can be selected. |
Details
When using the default data
argument, a window will pop up to ask in what file the data can be found. This text file containing the data should consist of two columns for single-case phase and alternation designs: the first with the condition labels and the second with the obtained scores.
For multiple-baseline designs it should consist of these two columns for EACH unit. This way, each row represents one measurement occasion. It is important not to label the rows or columns.
For multiple baseline designs, when using the default starts
argument, second a window pops up in which is asked in what file the possible start points can be found. In this startpoint file, each row should contain all possibilities for one unit, separated by a tab. The rows and columns should not be labeled.
For user specified designs, when using the default assignments
argument, second a window pops up in which is asked in what file all the possible assignments can be found. In this file, each row should contain the sequence of conditions in one possible assignment, separated by a tab. There should be one row for every possible assignment. The rows and columns should not be labeled.
Missing data should be indicated as NA
. When there is missing data, randomization distribution is generated as usual, but instead of randomly reshuffling numerical scores only, the missing data markers (NA
) are also included in the reshuffling. For test statistic calculations, missing data are omitted.
When choosing to save the randomization distribution to a file, next a window will pop up (for multiple baseline designs this is the third pop-up window, for all other designs it is the second window) to ask where to save it. This location can be an existing file, as well as a new file that can be created by giving a file name and the extension .txt. In this latter case a confirmation is required ("The file does not exist yet. Create the file?").
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Bulte, I., & Onghena, P. (2009). Randomization tests for multiple baseline designs: An extension of the SCRT-R package. Behavior Research Methods, 41, 477-485.
Edgington, E.S., & Onghena, P. (2007). Randomization Tests (4th ed.). Boca Raton, FL: Chapman & Hall/CRC.
http://ppw.kuleuven.be/home/english/research/mesrg
See Also
pvalue.systematic
to obtain the corresponding p-value for the exhaustive randomization distribution.
observed
to calculate the observed test statistic.
distribution.random
to generate the nonexhaustive randomization distribution and
pvalue.random
to obtain the corresponding p-value.
Examples
data(ABAB)
distribution.systematic(design = "ABAB", statistic = "PA-PB",
save = "no", limit = 4, data = ABAB)
Graphical representation of single-case data
Description
The observed single-case data are plotted.
Usage
graph1(design,data=read.table(file.choose(new=FALSE)),
xlab="Measurement Times",ylab="Scores")
Arguments
design |
Type of single-case design: |
data |
File in which the data can be found. Default: a window pops up in which the file can be selected. |
xlab |
Label x axis |
ylab |
Label y axis |
Details
When using the default data
argument, a window will pop up to ask in what file the data can be found. This text file containing the data should consist of two columns for single-case phase and alternation designs: the first with the condition labels and the second with the obtained scores. For multiple-baseline designs it should consist of these two columns for EACH unit. This way, each row represents one measurement occasion. It is important not to label the rows or columns.
For alternation designs, after the plot is drawn, the location of the legend should be indicated by a left mouse click.
Missing data should be indicated as NA
. For calculations, missing data are omitted.
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Bulte, I., & Onghena, P. (2009). Randomization tests for multiple baseline designs: An extension of the SCRT-R package. Behavior Research Methods, 41, 477-485.
Bulte, I., & Onghena, P. (in press). When the Truth Hits You Between the Eyes: A Software Tool for the Visual Analysis of Single-Case Experimental Data. Manuscript accepted for publication in Methodology.
http://ppw.kuleuven.be/home/english/research/mesrg
Examples
data(ABAB)
graph1(design = "ABAB", data = ABAB)
Observed test statistic
Description
The observed test statistic is calculated from the obtained raw data.
Usage
observed(design, statistic, data = read.table(file.choose(new = FALSE)))
Arguments
design |
Type of single-case design: |
statistic |
Test statistic. For alternation designs, multiple-baseline designs and AB phase designs, there are 3 built-in possibilities: |
data |
File in which the data can be found. Default: a window pops up in which the file can be selected. |
Details
When using the default data
argument, a window will pop up to ask in what file the data can be found. This text file containing the data should consist of two columns for single-case phase and alternation designs: the first with the condition labels and the second with the obtained scores.
For multiple-baseline designs it should consist of these two columns for EACH unit. This way, each row represents one measurement occasion. It is important not to label the rows or columns.
Missing data should be indicated as NA
. For calculations, missing data are omitted.
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Bulte, I., & Onghena, P. (2009). Randomization tests for multiple baseline designs: An extension of the SCRT-R package. Behavior Research Methods, 41, 477-485.
http://ppw.kuleuven.be/home/english/research/mesrg
See Also
distribution.systematic
to generate the exhaustive randomization distribtion and
pvalue.systematic
to obtain the corresponding p-value.
distribution.random
to generate the nonexhaustive randomization distribution and
pvalue.random
to obtain the corresponding p-value.
Examples
data(ABAB)
observed(design = "ABAB", statistic = "PA-PB", data = ABAB)
P-value using the Monte Carlo procedure
Description
The P-value corresponding to the observed value of the test statistic is obtained by locating this value in the randomization distribution generated by a random sample of all assignment possibilities (the nonexhaustive randomization distribution).
Usage
pvalue.random(design, statistic, save = "no",
number, limit, data = read.table(file.choose(new = FALSE)),
starts = file.choose(new = FALSE), assignments = file.choose(new = FALSE))
Arguments
design |
Type of single-case design: |
statistic |
Test statistic. For alternation designs, multiple-baseline designs and AB phase designs, there are 3 built-in possibilities: |
save |
Save the randomization distribution to a file ( |
number |
Number of randomizations required. Please note that the observed test statistic is always included in the randomization distribution. |
limit |
For phase designs: minimum number of observations per phase. For alternating treatments designs: maximum number of consecutive administrations of the same condition. |
data |
File in which the data can be found. Default: a window pops up in which the file can be selected. |
starts |
Only for multiple baseline designs: location of the file where the possible start points can be found. Default: a window pops up in which the file can be selected. |
assignments |
Only for user specified designs: location of the file where all the possible assignments can be found. Default: a window pops up in which the file can be selected. |
Details
When using the default data
argument, a window will pop up to ask in what file the data can be found. This text file containing the data should consist of two columns for single-case phase and alternation designs: the first with the condition labels and the second with the obtained scores.
For multiple-baseline designs it should consist of these two columns for EACH unit. This way, each row represents one measurement occasion. It is important not to label the rows or columns.
For multiple baseline designs, when using the default starts
argument, second a window pops up in which is asked in what file the possible start points can be found. In this startpoint file, each row should contain all possibilities for one unit, separated by a tab. The rows and columns should not be labeled.
For user specified designs, when using the default assignments
argument, second a window pops up in which is asked in what file all the possible assignments can be found. In this file, each row should contain the sequence of conditions in one possible assignment, separated by a tab. There should be one row for every possible assignment. The rows and columns should not be labeled.
Missing data should be indicated as NA
. When there is missing data, randomization distribution is generated as usual, but instead of randomly reshuffling numerical scores only, the missing data markers (NA
) are also included in the reshuffling. For test statistic calculations, missing data are omitted. If test statistic cannot be calculated for a particular randomization due to insufficient data for a treatment condition, the test statistic from this randomization is conservatively considered more extreme than the observed test statistic.
When choosing to save the randomization distribution to a file, next a window will pop up (for multiple baseline designs or user specified designs this is the third pop-up window, for all other designs it is the second window) to ask where to save it. This location can be an existing file, as well as a new file that can be created by giving a file name and the extension .txt. In this latter case a confirmation is required ("The file does not exist yet. Create the file?").
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Bulte, I., & Onghena, P. (2009). Randomization tests for multiple baseline designs: An extension of the SCRT-R package. Behavior Research Methods, 41, 477-485.
Edgington, E.S., & Onghena, P. (2007). Randomization Tests (4th ed.). Boca Raton, FL: Chapman & Hall/CRC.
Hope, A.C.A. (1968). A simplified Monte Carlo significance test procedure. Journal of the Royal Statistical Society, Series B 30, 582-598.
Onghena, P. & May, R.B. (1995). Pitfalls in computing and interpreting randomization test p values: A commentary on Chen and Dunlap. Behavior Research Methods, Instruments, & Computers, 27, 408-411.
http://ppw.kuleuven.be/home/english/research/mesrg
See Also
distribution.random
to generate the corresponding nonexhaustive randomization distribution.
observed
to calculate the observed test statistic.
distribution.systematic
to generate the exhaustive randomization distribution and
pvalue.systematic
to obtain the corresponding p-value.
Examples
data(ABAB)
pvalue.random(design = "ABAB", statistic = "PA-PB", save = "no",
number = 100, limit = 4, data = ABAB)
P-value using the systematic procedure
Description
The P-value corresponding to the observed value of the test statistic is obtained by locating this value in the randomization distribution generated by complete enumeration of all assignment possibilities (the exhaustive randomization distribution).
Usage
pvalue.systematic(design, statistic, save = "no",
limit, data = read.table(file.choose(new = FALSE)),
starts = file.choose(new = FALSE), assignments = file.choose(new = FALSE))
Arguments
design |
Type of single-case design: |
statistic |
Test statistic. For alternation designs, multiple-baseline designs and AB phase designs, there are 3 built-in possibilities: |
save |
Save the randomization distribution to a file ( |
limit |
For phase designs: minimum number of observations per phase. For alternating treatments designs: maximum number of consecutive administrations of the same condition. |
data |
File in which the data can be found. Default: a window pops up in which the file can be selected. |
starts |
Only for multiple baseline designs: location of the file where the possible start points can be found. Default: a window pops up in which the file can be selected. |
assignments |
Only for user specified designs: location of the file where all the possible assignments can be found. Default: a window pops up in which the file can be selected. |
Details
When using the default data
argument, a window will pop up to ask in what file the data can be found. This text file containing the data should consist of two columns for single-case phase and alternation designs: the first with the condition labels and the second with the obtained scores.
For multiple-baseline designs it should consist of these two columns for EACH unit. This way, each row represents one measurement occasion. It is important not to label the rows or columns.
For multiple baseline designs, when using the default starts
argument, second a window pops up in which is asked in what file the possible start points can be found. In this startpoint file, each row should contain all possibilities for one unit, separated by a tab. The rows and columns should not be labeled.
For user specified designs, when using the default assignments
argument, second a window pops up in which is asked in what file all the possible assignments can be found. In this file, each row should contain the sequence of conditions in one possible assignment, separated by a tab. There should be one row for every possible assignment. The rows and columns should not be labeled.
Missing data should be indicated as NA
. When there is missing data, randomization distribution is generated as usual, but instead of randomly reshuffling numerical scores only, the missing data markers (NA
) are also included in the reshuffling. For test statistic calculations, missing data are omitted. If test statistic cannot be calculated for a particular randomization due to insufficient data for a treatment condition, the test statistic from this randomization is conservatively considered more extreme than the observed test statistic.
When choosing to save the randomization distribution to a file, next a window will pop up (for multiple baseline designs or user specified designs this is the third pop-up window, for all other designs it is the second window) to ask where to save it. This location can be an existing file, as well as a new file that can be created by giving a file name and the extension .txt. In this latter case a confirmation is required ("The file does not exist yet. Create the file?").
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Bulte, I., & Onghena, P. (2009). Randomization tests for multiple baseline designs: An extension of the SCRT-R package. Behavior Research Methods, 41, 477-485.
Edgington, E.S., & Onghena, P. (2007). Randomization Tests (4th ed.). Boca Raton, FL: Chapman & Hall/CRC.
http://ppw.kuleuven.be/home/english/research/mesrg
See Also
distribution.systematic
to generate the corresponding exhaustive randomization distribution.
observed
to calculate the observed test statistic.
distribution.random
to generate the nonexhaustive randomization distribution and
pvalue.random
to obtain the corresponding p-value.
Examples
data(ABAB)
pvalue.systematic(design = "ABAB", statistic = "PA-PB", save = "no",
limit = 4, data = ABAB)
Number of assignment possibilities
Description
The number of assignment possibilities for the specified design is calculated.
Usage
quantity(design, MT, limit, starts = file.choose(new = FALSE),
assignments = file.choose(new = FALSE))
Arguments
design |
Type of single-case design: |
MT |
Measurement times: number of observations. |
limit |
For phase designs: minimum number of observations per phase. For alternating treatments designs: maximum number of consecutive administrations of the same condition. |
starts |
Only for multiple baseline designs: location of the file where the possible start points can be found. Default: a window pops up in which the file can be selected. |
assignments |
Only for user specified designs: location of the file where all the possible assignments can be found. Default: a window pops up in which the file can be selected. |
Details
For multiple baseline designs, when using the default starts
argument, only the design
argument is required. In this default version a window pops up in which is asked in what file the possible start points can be found. In this startpoint file, each row should contain all possibilities for one unit, separated by a tab. The rows and columns should not be labeled.
The number of possible assignments for a multiple baseline design is calculated assuming NO overlap between the possible start points of the different units (staggered administration).
For user specified designs, when using the default assignments
argument, a window pops up in which is asked in what file all the possible assignments can be found. In this file, each row should contain the sequence of conditions in one possible assignment, separated by a tab. There should be one row for every possible assignment. The rows and columns should not be labeled.
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Bulte, I., & Onghena, P. (2009). Randomization tests for multiple baseline designs: An extension of the SCRT-R package. Behavior Research Methods, 41, 477-485.
http://ppw.kuleuven.be/home/english/research/mesrg
See Also
assignments
to enumerate all assignment possibilities.
selectdesign
to randomly select one of the assignment possibilities.
Examples
quantity(design = "ABAB", MT = 24, limit = 4)
Selection on one assignment possibility
Description
One assignment possibility is randomly selected from all theoretical possibilities.
Usage
selectdesign(design, MT, limit, starts = file.choose(new=FALSE),
assignments = file.choose(new = FALSE))
Arguments
design |
Type of single-case design: |
MT |
Measurement times: number of observations. |
limit |
For phase designs: minimum number of observations per phase. For alternating treatments designs: maximum number of consecutive administrations of the same condition. |
starts |
Only for multiple baseline designs: location of the file where the possible start points can be found. Default: a window pops up in which the file can be selected. |
assignments |
Only for user specified designs: location of the file where all the possible assignments can be found. Default: a window pops up in which the file can be selected. |
Details
For multiple baseline designs, when using the default starts
argument, only the design
argument is required. In this default version a window pops up in which is asked in what file the possible start points can be found. In this startpoint file, each row should contain all possibilities for one unit, separated by a tab. The rows and columns should not be labeled.
For user specified designs, when using the default assignments
argument, first a window pops up in which is asked in what file all the possible assignments can be found. In this file, each row should contain the sequence of conditions in one possible assignment, separated by a tab. There should be one row for every possible assignment. The rows and columns should not be labeled.
For multiple baseline designs, a possible combination of start points for each unit is returned. For all other designs, a possible sequence of conditions is returned (e.g., "A" "A" "A" "A" "B" "B" "B").
References
Bulte, I., & Onghena, P. (2008). An R package for single-case randomization tests. Behavior Research Methods, 40, 467-478.
Bulte, I., & Onghena, P. (2009). Randomization tests for multiple baseline designs: An extension of the SCRT-R package. Behavior Research Methods, 41, 477-485.
http://ppw.kuleuven.be/home/english/research/mesrg
See Also
quantity
to calculate the number of assignment possibilities.
assignments
to enumerate all assignment possibilities.
Examples
selectdesign(design = "ABAB", MT = 24, limit = 4)