create_null_rand {Counternull} | R Documentation |

## Create Null Randomization Distribution

### Description

Generates null randomization distribution for a given test statistic.

### Usage

```
create_null_rand(
y,
w,
rand_matrix,
test_stat = NULL,
fun = NULL,
alternative = NULL,
bw = NULL
)
```

### Arguments

`y` |
Vector of observed outcomes |

`w` |
Vector indicating treatment assignments |

`rand_matrix` |
Matrix with permutations for experiment assignments |

`test_stat` |
Name of built in test statistic function. Provide "diffmeans" for difference of means, "t" for t test, "paired-t" for paired t test, and "cohens-d" for cohen's d test (optional). |

`fun` |
Test statistic function (optional). |

`alternative` |
Character string specifying alternative hypothesis. Must be one of "two-sided" (default), "greater", or "less". |

`bw` |
Bin width for histogram (optional) |

### Details

Call summary on "null_rand" class to retrieve information on the null randomization distribution. Call plot on "null_rand" class for visualization of null randomization distribution.

Assignments must be indicated in arguments "w" and "rand_matrix" using numeric 1 or 0.

Argument "rand_matrix" must have assignment permutations in each column and must have the same number of rows as there are entries in "w".

One of either argument "test_stat" or "fun" must be specified.

Argument "fun" must take in two parameters (treated outcomes and control outcomes) and returns a numeric test statistic value (scalar).

### Value

Class "null_rand" with 11 entries:

- null_dist
Vector of permuted test statistics under the null hypothesis

- t_obs
Observed test statistic

- counts
Number of test statistics more extreme than observed test statistic

- pvalue
Fisher-Exact P-value

- alternative
Specified alternative

- rand_matrix
Randomization matrix used to generate null distribution

- bin_width
Specified bin width

- y
Observed outcomes

- w
Vector indicating treatment assignments

- test_stat
Name of built in test statistic function

- fun
Test statistic function

### Examples

```
y = sample_data$turn_angle
w = sample_data$w
n_r = create_null_rand(y, w, sample_matrix, test_stat = c("t"))
summary(n_r)
plot(n_r)
```

*Counternull*version 0.2.12 Index]