@@ -45,6 +45,7 @@ <h2>bootlm</h2>
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-- Function File: [STATS, BOOTSTAT] = bootlm (...)
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-- Function File: [STATS, BOOTSTAT, AOVSTAT] = bootlm (...)
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-- Function File: [STATS, BOOTSTAT, AOVSTAT, PRED_ERR] = bootlm (...)
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+ -- Function File: [STATS, BOOTSTAT, AOVSTAT, PRED_ERR, X] = bootlm (...)
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Fits a linear model with categorical and/or continuous predictors (i.e.
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independent variables) on a continuous outcome (i.e. dependent variable)
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By default, confidence intervals and Null Hypothesis Significance Tests
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(NHSTs) for the regression coefficients (H0 = 0) are calculated by wild
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bootstrap-t and are robust when normality and homoscedasticity cannot be
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- assumed.
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+ assumed [1] .
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Usage of this function is very similar to that of 'anovan'. Data (Y)
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is a numeric variable, and the predictor(s) are specified in GROUP (a.k.a.
@@ -136,11 +137,11 @@ <h2>bootlm</h2>
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o 'wild' (default): Wild bootstrap-t, using the 'bootwild'
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function. Please see the help documentation below and in the
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- function 'bootwild' for more information about this method.
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+ function 'bootwild' for more information about this method [1] .
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o 'bayesian': Bayesian bootstrap, using the 'bootbayes' function.
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Please see the help documentation below and in the function
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- 'bootbayes' for more information about this method.
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+ 'bootbayes' for more information about this method [2] .
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Note that p-values are a frequentist concept and are only computed
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and returned from bootlm when the METHOD is 'wild'. Since the wild
@@ -165,7 +166,7 @@ <h2>bootlm</h2>
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o 'auto': Sets a value for PRIOR that effectively incorporates
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Bessel's correction a priori such that the variance of the
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- posterior (i.e. the rows of BOOTSTAT) becomes an unbiased
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+ posterior (i.e. of the rows of BOOTSTAT) becomes an unbiased
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estimator of the sampling variance*. The calculation used for
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'auto' is as follows:
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@@ -187,7 +188,7 @@ <h2>bootlm</h2>
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to Bayes rule: a uniform (or flat) Dirichlet distribution
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(over all points in its support). Please see the help
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documentation for the function 'bootbayes' for more information
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- about the prior.
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+ about the prior [2] .
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'[...] = bootlm (Y, GROUP, ..., 'alpha', ALPHA)'
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@@ -198,16 +199,16 @@ <h2>bootlm</h2>
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o scalar: Set the central mass of the intervals to 100*(1-ALPHA)%.
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For example, 0.05 for a 95% interval. If METHOD is 'wild',
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then the intervals are symmetric bootstrap-t confidence
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- intervals. If METHOD is 'bayesian', then the intervals are
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- shortest probability credible intervals.
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+ intervals [1] . If METHOD is 'bayesian', then the intervals
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+ are shortest probability credible intervals [2] .
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o vector: A pair of probabilities defining the lower and upper
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and upper bounds of the interval(s) as 100*(ALPHA(1))% and
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100*(ALPHA(2))% respectively. For example, [.025, .975] for
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a 95% interval. If METHOD is 'wild', then the intervals are
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- asymmetric bootstrap-t confidence intervals. If METHOD is
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+ asymmetric bootstrap-t confidence intervals [1] . If METHOD is
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'bayesian', then the intervals are simple percentile credible
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- intervals.
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+ intervals [2] .
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The default value of ALPHA is the scalar: 0.05.
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@@ -412,7 +413,7 @@ <h2>bootlm</h2>
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- 'CI_lower': The lower bound(s) of the confidence/credible interval(s)
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- 'CI_upper': The upper bound(s) of the confidence/credible interval(s)
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- 'pval': The p-value(s) for the hypothesis that the estimate(s) == 0
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- - 'fpr': The minimum false positive risk (FPR) for each p-value
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+ - 'fpr': The minimum false positive risk (FPR) for each p-value [3].
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- 'N': The number of independent sampling units used to compute CIs
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- 'prior': The prior used for Bayesian bootstrap. This will return a
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scalar for regression coefficients, or a P x 1 or P x 2
@@ -445,7 +446,7 @@ <h2>bootlm</h2>
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- 'MS': Mean-squares
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- 'F': F-Statistic
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- 'PVAL': p-values
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- - 'FPR': The minimum false positive risk for each p-value
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+ - 'FPR': The minimum false positive risk for each p-value [3]
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- 'SSE': Sum-of-Squared Error
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- 'DFE': Degrees of Freedom for Error
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- 'MSE': Mean Squared Error
@@ -459,8 +460,8 @@ <h2>bootlm</h2>
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the method used is 'wild' bootstrap AND when no other statistics are
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requested (i.e. estimated marginal means or posthoc tests). The
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bootstrap is achieved by wild bootstrap of the residuals from the full
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- model. Computations of the statistics in AOVSTAT are compatible with
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- the 'clustid' and 'blocksz' options.
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+ model [1,4] . Computations of the statistics in AOVSTAT are compatible
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+ with the 'clustid' and 'blocksz' options.
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The bootlm function treats all model predictors as fixed effects during
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ANOVA tests. While any type of predictor, be it a fixed effect or
@@ -478,13 +479,13 @@ <h2>bootlm</h2>
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sample sizes are equal or not.
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'[STATS, BOOTSTAT, AOVSTAT, PRED_ERR] = bootlm (...)' also computes
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- refined bootstrap estimates of prediction error* and returns the derived
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- statistics in a structure with the following fields:
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+ refined bootstrap estimates of prediction error* and returns statistics
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+ derived from it in a structure containing the following fields:
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- 'MODEL': The formula of the linear model(s) in Wilkinson's notation
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- - 'PE': Bootstrap estimate of prediction error
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+ - 'PE': Bootstrap estimate of prediction error [5]
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- 'PRESS': Bootstrap estimate of predicted residual error sum of squares
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- 'RSQ_pred': Bootstrap estimate of predicted R-squared
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- - 'EIC': Extended (Efron) Information Criterion
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+ - 'EIC': Extended (Efron) Information Criterion [6]
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- 'RL': Relative likelihood (compared to the intercept-only model)
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- 'Wt': EIC expressed as weights
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@@ -501,7 +502,30 @@ <h2>bootlm</h2>
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installed and loaded, then these computations will be automatically
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accelerated by parallel processing on platforms with multiple processors
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- bootlm (version 2024.05.17)
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+ '[STATS, BOOTSTAT, AOVSTAT, PRED_ERR, MAT] = bootlm (...)' also returns
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+ a structure containing the design matrix of the predictors (X), the
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+ regression coefficients (b), the hypothesis matrix (L) and the outcome (Y)
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+ for the linear model.
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+
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+ Bibliography:
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+ [1] Penn, A.C. statistics-resampling manual: `bootwild` function reference.
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+ https://gnu-octave.github.io/statistics-resampling/function/bootwild.html
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+ and references therein. Last accessed 02 Sept 2024.
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+ [2] Penn, A.C. statistics-resampling manual: `bootbayes` function reference.
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+ https://gnu-octave.github.io/statistics-resampling/function/bootbayes.html
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+ and references therein. Last accessed 02 Sept 2024.
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+ [3] David Colquhoun (2019) The False Positive Risk: A Proposal Concerning
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+ What to Do About p-Values, The American Statistician, 73:sup1, 192-201
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+ [4] ter Braak (1992) Permutation versus bootstrap significance test in
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+ multiple regression and ANOVA. In Jockel et al (Eds.) Bootstrapping
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+ and Related Techniques. Springer-Verlag, Berlin, pg 79-86
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+ [5] Efron and Tibshirani (1993) An Introduction to the Bootstrap.
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+ New York, NY: Chapman & Hall. pg 247-252
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+ [6] Konishi & Kitagawa (2008), "Bootstrap Information Criterion" In:
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+ Information Criteria and Statistical Modeling. Springer Series in
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+ Statistics. Springer, NY.
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+
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+ bootlm (version 2024.07.08)
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Author: Andrew Charles Penn
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https://www.researchgate.net/profile/Andrew_Penn/
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