In case of two independent populations \(N(\mu_1,\sigma^2)\) and \(N(\mu_2,\sigma^2)\) with unknown common variance \(\sigma^2\), consider the two-sample \(t\)-test for testing the point null hypothesis of difference in their means \(H_0 : \mu_2 - \mu_1 = 0\) against \(H_1 : \mu_2 - \mu_1 \neq 0\). Based on an observed data, this function calculates the Hajnal's ratio in favor of \(H_1\) when the prior assumed under the alternative on the difference between standardized effect sizes \((\mu_2 - \mu_1)/\sigma\) places equal probability at \(+\delta\) and \(-\delta\) (\(\delta>0\) prefixed).
HajnalBF_twot(obs1, obs2, n1Obs, n2Obs, mean.obs1, mean.obs2,
sd.obs1, sd.obs2, test.statistic, es1 = 0.3)
Numeric vector. Observed vector of data from Group-1.
Numeric vector. Observed vector of data from Group-2.
Numeric or numeric vector. Sample size(s) from Group-1. Same as length(obs1)
when numeric.
Numeric or numeric vector. Sample size(s) from Group-2. Same as length(obs2)
when numeric.
Numeric or numeric vector. Sample mean(s) from Group-1. Same as mean(obs1)
when numeric.
Numeric or numeric vector. Sample mean(s) from Group-2. Same as mean(obs2)
when numeric.
Numeric or numeric vector. Sample standard deviations(s) from Group-1. Same as sd(obs1)
when numeric.
Numeric or numeric vector. Sample standard deviations(s) from Group-2. Same as sd(obs2)
when numeric.
Numeric or numeric vector. Test-statistic value(s).
Positive numeric. \(\delta\) as above. Default: \(0.3\). For this, the prior on \((\mu_2 - \mu_1)/\sigma\) takes values \(0.3\) and \(-0.3\) each with equal probability 1/2.
Positive numeric or numeric vector. The Hajnal's ratio(s).
A user can either specify obs1
and obs2
, or n1Obs
, n2Obs
, mean.obs1
, mean.obs2
, sd.obs1
and sd.obs2
, or n1Obs
, n2Obs
, and test.statistic
.
If obs1
and obs2
are provided, it returns the corresponding Bayes factor value.
If n1Obs
, n2Obs
, mean.obs1
, mean.obs2
, sd.obs1
and sd.obs2
are provided, the function is vectorized over the arguments. Bayes factor values corresponding to the values therein are returned.
If n1Obs
, n2Obs
, and test.statistic
are provided, the function is vectorized over each of the arguments. Bayes factor values corresponding to the values therein are returned.
Hajnal, J. (1961). A two-sample sequential t-test.Biometrika, 48:65-75, [Article].
Schnuerch, M. and Erdfelder, E. (2020). A two-sample sequential t-test.Biometrika, 48:65-75, [Article].
# NOT RUN {
HajnalBF_twot(obs1 = rnorm(100), obs2 = rnorm(100))
# }
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