safeZTest {safestats}

Safe Z-Test

Description

Safe one and two sample z-tests on vectors of data. The function is modelled after t.test().

Usage

safeZTest(
  x,
  y = NULL,
  paired = FALSE,
  designObj = NULL,
  pilot = FALSE,
  ciValue = NULL,
  tol = 1e-05,
  na.rm = FALSE,
  ...
)

safe.z.test(
  x,
  y = NULL,
  paired = FALSE,
  designObj = NULL,
  pilot = FALSE,
  tol = 1e-05,
  ...
)

Arguments

x

a (non-empty) numeric vector of data values.

y

an optional (non-empty) numeric vector of data values.

paired

a logical indicating whether you want the paired z-test.

designObj

an object obtained from designSafeZ(), or NULL, when pilot is set to TRUE.

pilot

a logical indicating whether a pilot study is run. If TRUE, it is assumed that the number of samples is exactly as planned. The default null h0=1 is used, alpha=0.05, and alternative="twoSided" is used. To change these default values, please use designSafeZ().

ciValue

numeric is the ciValue-level of the confidence sequence. Default ciValue=NULL, and ciValue = 1 - alpha

tol

numeric > 0, only used if pilot equals TRUE, as it then specifies the mesh used to find the test defining parameter to construct a pilot design object.

na.rm

a logical value indicating whether NA values should be stripped before the computation proceeds.

...

further arguments to be passed to or from methods.

Value

Returns an object of class 'safeTest'. An object of class 'safeTest' is a list containing at least the following components:

statistic

the value of the test statistic. Here the z-statistic.

n

The realised sample size(s).

eValue

the e-value of the safe test.

confInt

To be implemented: a safe confidence interval for the mean appropriate to the specific alternative hypothesis.

estimate

the estimated mean or difference in means or mean difference depending on whether it was a one- sample test or a two-sample test.

h0

the specified hypothesised value of the mean or mean difference depending on whether it was a one-sample or a two-sample test.

testType

any of "oneSample", "paired", "twoSample" effectively provided by the user.

dataName

a character string giving the name(s) of the data.

designObj

an object of class "safeDesign" described in designSafeZ().

call

the expression with which this function is called.

Examples

designObj <- designSafeZ(meanDiffMin=0.6, alpha=0.008,
                         alternative="greater", testType="twoSample",
                         ratio=1.2)

set.seed(1)
x <- rnorm(100)
y <- rnorm(100)
safeZTest(x, y, designObj=designObj)      #

safeZTest(1:10, y = c(7:20), pilot=TRUE, alternative="less")      # s = 7.7543e+20 > 1/alpha