Skip to contents

This function takes as input a value of the Log-Likelihood Ratio and returns a table that shows the impact on some simulated prior probabilities for the prosecution hypothesis.

Usage

posterior(LLR)

Arguments

LLR

One single numeric value corresponding to a Log-Likelihood Ratio (base 10).

Value

A data frame containing some simulated prior probabilities/odds for the prosecution and the resulting posterior probabilities/odds after the LLR.

Examples

posterior(LLR = 0)
#> # A tibble: 11 × 6
#>    prosecution_prior_probs prior_odds   LLR    LR  post_odds
#>                      <dbl>      <dbl> <dbl> <dbl>      <dbl>
#>  1                0.000001 0.00000100     0     1 0.00000100
#>  2                0.01     0.0101         0     1 0.0101    
#>  3                0.1      0.111          0     1 0.111     
#>  4                0.2      0.25           0     1 0.25      
#>  5                0.3      0.429          0     1 0.429     
#>  6                0.4      0.667          0     1 0.667     
#>  7                0.5      1              0     1 1         
#>  8                0.6      1.5            0     1 1.5       
#>  9                0.7      2.33           0     1 2.33      
#> 10                0.8      4              0     1 4         
#> 11                0.9      9              0     1 9         
#> # ℹ 1 more variable: prosecution_post_probs <dbl>
posterior(LLR = 1.8)
#> # A tibble: 11 × 6
#>    prosecution_prior_probs prior_odds   LLR    LR   post_odds
#>                      <dbl>      <dbl> <dbl> <dbl>       <dbl>
#>  1                0.000001 0.00000100   1.8  63.1   0.0000631
#>  2                0.01     0.0101       1.8  63.1   0.637    
#>  3                0.1      0.111        1.8  63.1   7.01     
#>  4                0.2      0.25         1.8  63.1  15.8      
#>  5                0.3      0.429        1.8  63.1  27.0      
#>  6                0.4      0.667        1.8  63.1  42.1      
#>  7                0.5      1            1.8  63.1  63.1      
#>  8                0.6      1.5          1.8  63.1  94.6      
#>  9                0.7      2.33         1.8  63.1 147.       
#> 10                0.8      4            1.8  63.1 252.       
#> 11                0.9      9            1.8  63.1 568.       
#> # ℹ 1 more variable: prosecution_post_probs <dbl>
posterior(LLR = -0.5)
#> # A tibble: 11 × 6
#>    prosecution_prior_probs prior_odds   LLR    LR   post_odds
#>                      <dbl>      <dbl> <dbl> <dbl>       <dbl>
#>  1                0.000001 0.00000100  -0.5 0.316 0.000000316
#>  2                0.01     0.0101      -0.5 0.316 0.00319    
#>  3                0.1      0.111       -0.5 0.316 0.0351     
#>  4                0.2      0.25        -0.5 0.316 0.0791     
#>  5                0.3      0.429       -0.5 0.316 0.136      
#>  6                0.4      0.667       -0.5 0.316 0.211      
#>  7                0.5      1           -0.5 0.316 0.316      
#>  8                0.6      1.5         -0.5 0.316 0.474      
#>  9                0.7      2.33        -0.5 0.316 0.738      
#> 10                0.8      4           -0.5 0.316 1.26       
#> 11                0.9      9           -0.5 0.316 2.85       
#> # ℹ 1 more variable: prosecution_post_probs <dbl>
posterior(LLR = 4)
#> # A tibble: 11 × 6
#>    prosecution_prior_probs prior_odds   LLR    LR  post_odds
#>                      <dbl>      <dbl> <dbl> <dbl>      <dbl>
#>  1                0.000001 0.00000100     4 10000     0.0100
#>  2                0.01     0.0101         4 10000   101.    
#>  3                0.1      0.111          4 10000  1111.    
#>  4                0.2      0.25           4 10000  2500     
#>  5                0.3      0.429          4 10000  4286.    
#>  6                0.4      0.667          4 10000  6667.    
#>  7                0.5      1              4 10000 10000     
#>  8                0.6      1.5            4 10000 15000     
#>  9                0.7      2.33           4 10000 23333.    
#> 10                0.8      4              4 10000 40000     
#> 11                0.9      9              4 10000 90000     
#> # ℹ 1 more variable: prosecution_post_probs <dbl>