Skip to contents

Confidence intervals for semipartial correlation coefficients are generated using the SCorNB() function from the betaNB package. In this example, we use the data set and the model used in betaNB: Example Using the BetaNB Function.

df <- betaNB::nas1982

Regression

Fit the regression model using the lm() function.

object <- lm(QUALITY ~ NARTIC + PCTGRT + PCTSUPP, data = df)

Nonparametric Bootstrap

nb <- NB(object)

Semipartial Correlation Coefficients

Normal-Theory Approach

out <- SCorNB(nb, alpha = 0.05)

Methods

summary

Summary of the results of SCorNB().

Percentile Confidence Intervals

summary(out, type = "pc")
#> Call:
#> SCorNB(object = nb, alpha = 0.05)
#> 
#> Semipartial correlations
#> type = "pc"
#>            est     se    R   2.5%  97.5%
#> NARTIC  0.4312 0.0707 5000 0.2842 0.5629
#> PCTGRT  0.3430 0.0731 5000 0.1838 0.4744
#> PCTSUPP 0.2385 0.0702 5000 0.0958 0.3689

Bias Corrected Confidence Intervals

summary(out, type = "bc")
#> Call:
#> SCorNB(object = nb, alpha = 0.05)
#> 
#> Semipartial correlations
#> type = "bc"
#>            est     se    R   2.5%  97.5%
#> NARTIC  0.4312 0.0707 5000 0.3024 0.5797
#> PCTGRT  0.3430 0.0731 5000 0.2100 0.4996
#> PCTSUPP 0.2385 0.0702 5000 0.1071 0.3856

Bias Corrected and Accelerated Confidence Intervals

summary(out, type = "bca")
#> Call:
#> SCorNB(object = nb, alpha = 0.05)
#> 
#> Semipartial correlations
#> type = "bca"
#>            est     se    R   2.5%  97.5%
#> NARTIC  0.4312 0.0707 5000 0.3087 0.5906
#> PCTGRT  0.3430 0.0731 5000 0.2196 0.5138
#> PCTSUPP 0.2385 0.0702 5000 0.1034 0.3822

coef

Return the vector of estimates.

coef(out)
#>    NARTIC    PCTGRT   PCTSUPP 
#> 0.4311525 0.3430075 0.2384789

vcov

Return the sampling covariance matrix.

vcov(out)
#>                NARTIC        PCTGRT       PCTSUPP
#> NARTIC   0.0050029466 -0.0004231678 -0.0007344594
#> PCTGRT  -0.0004231678  0.0053503126 -0.0008096115
#> PCTSUPP -0.0007344594 -0.0008096115  0.0049346860

confint

Return confidence intervals.

Percentile Confidence Intervals

confint(out, level = 0.95, type = "pc")
#>              2.5 %    97.5 %
#> NARTIC  0.28416656 0.5628525
#> PCTGRT  0.18377442 0.4744038
#> PCTSUPP 0.09578834 0.3688574

Bias Corrected Confidence Intervals

confint(out, level = 0.95, type = "bc")
#>             2.5 %    97.5 %
#> NARTIC  0.3024316 0.5796886
#> PCTGRT  0.2099740 0.4995694
#> PCTSUPP 0.1071179 0.3855923

Bias Corrected and Accelerated Confidence Intervals

confint(out, level = 0.95, type = "bca")
#>             2.5 %    97.5 %
#> NARTIC  0.3087198 0.5906212
#> PCTGRT  0.2196308 0.5138464
#> PCTSUPP 0.1033713 0.3822040

References