inferr

Tools for Statistical Inference

CRAN_Status_Badge R-CMD-check Coverage status

Overview

inferr builds upon the statistical tests provided in stats, provides additional and flexible input options and more detailed and structured test results. As of version 0.3, inferr includes a select set of parametric and non-parametric statistical tests which are listed below:

Installation

# install inferr from CRAN
install.packages("inferr")

# the development version from github
# install.packages("devtools")
devtools::install_github("rsquaredacademy/inferr")

Articles

Usage

One Sample t Test

ifr_os_t_test(hsb, write, mu = 50, type = 'all')
#>                               One-Sample Statistics                               
#> ---------------------------------------------------------------------------------
#>  Variable    Obs     Mean     Std. Err.    Std. Dev.    [95% Conf. Interval] 
#> ---------------------------------------------------------------------------------
#>   write      200    52.775     0.6702       9.4786       51.4537    54.0969   
#> ---------------------------------------------------------------------------------
#> 
#>                                   Two Tail Test                                  
#>                                  ---------------                                  
#> 
#>                                Ho: mean(write) ~=50                              
#>                                Ha: mean(write) !=50                               
#> --------------------------------------------------------------------------------
#>  Variable      t      DF       Sig       Mean Diff.    [95% Conf. Interval] 
#> --------------------------------------------------------------------------------
#>   write      4.141    199    0.00005       2.775         1.4537     4.0969   
#> --------------------------------------------------------------------------------

ANOVA

ifr_oneway_anova(hsb, write, prog)
#>                                 ANOVA                                  
#> ----------------------------------------------------------------------
#>                    Sum of                                             
#>                    Squares     DF     Mean Square      F        Sig.  
#> ----------------------------------------------------------------------
#> Between Groups    3175.698      2      1587.849      21.275      0    
#> Within Groups     14703.177    197      74.635                        
#> Total             17878.875    199                                    
#> ----------------------------------------------------------------------
#> 
#>                  Report                   
#> -----------------------------------------
#> Category     N       Mean      Std. Dev. 
#> -----------------------------------------
#>    1        45      51.333       9.398   
#>    2        105     56.257       7.943   
#>    3        50      46.760       9.319   
#> -----------------------------------------
#> 
#> Number of obs = 200       R-squared     = 0.1776 
#> Root MSE      = 8.6392    Adj R-squared = 0.1693

Chi Square Test of Independence

ifr_chisq_assoc_test(hsb, female, schtyp)
#>                Chi Square Statistics                 
#> 
#> Statistics                     DF    Value      Prob 
#> ----------------------------------------------------
#> Chi-Square                     1    0.0470    0.8284
#> Likelihood Ratio Chi-Square    1    0.0471    0.8282
#> Continuity Adj. Chi-Square     1    0.0005    0.9822
#> Mantel-Haenszel Chi-Square     1    0.0468    0.8287
#> Phi Coefficient                     0.0153          
#> Contingency Coefficient             0.0153          
#> Cramer's V                          0.0153          
#> ----------------------------------------------------

Levene’s Test

ifr_levene_test(hsb, read, group_var = race)
#>            Summary Statistics             
#> Levels    Frequency    Mean     Std. Dev  
#> -----------------------------------------
#>   1          24        46.67      10.24   
#>   2          11        51.91      7.66    
#>   3          20        46.8       7.12    
#>   4          145       53.92      10.28   
#> -----------------------------------------
#> Total        200       52.23      10.25   
#> -----------------------------------------
#> 
#>                              Test Statistics                              
#> -------------------------------------------------------------------------
#> Statistic                            Num DF    Den DF         F    Pr > F 
#> -------------------------------------------------------------------------
#> Brown and Forsythe                        3       196      3.44    0.0179 
#> Levene                                    3       196    3.4792     0.017 
#> Brown and Forsythe (Trimmed Mean)         3       196    3.3936     0.019 
#> -------------------------------------------------------------------------

Cochran’s Q Test

ifr_cochran_qtest(exam, exam1, exam2, exam3)
#>    Test Statistics     
#> ----------------------
#> N                   15 
#> Cochran's Q       4.75 
#> df                   2 
#> p value          0.093 
#> ----------------------

McNemar Test

hb <- hsb
hb$himath <- ifelse(hsb$math > 60, 1, 0)
hb$hiread <- ifelse(hsb$read > 60, 1, 0)
ifr_mcnemar_test(hb, himath, hiread)
#>            Controls 
#> ---------------------------------
#> Cases       0       1       Total 
#> ---------------------------------
#>   0        135      21        156 
#>   1         18      26         44 
#> ---------------------------------
#> Total      153      47        200 
#> ---------------------------------
#> 
#>        McNemar's Test        
#> ----------------------------
#> McNemar's chi2        0.2308 
#> DF                         1 
#> Pr > chi2              0.631 
#> Exact Pr >= chi2      0.7493 
#> ----------------------------
#> 
#>        Kappa Coefficient         
#> --------------------------------
#> Kappa                     0.4454 
#> ASE                        0.075 
#> 95% Lower Conf Limit      0.2984 
#> 95% Upper Conf Limit      0.5923 
#> --------------------------------
#> 
#> Proportion With Factor 
#> ----------------------
#> cases             0.78 
#> controls         0.765 
#> ratio           1.0196 
#> odds ratio      1.1667 
#> ----------------------

Getting Help

If you encounter a bug, please file a minimal reproducible example using reprex on github. For questions and clarifications, use StackOverflow.