File size: 4,860 Bytes
5defafa
 
6e7dc3c
f335959
40d7b09
 
0765d8d
 
015b1a2
f335959
8a73f6f
f335959
f921051
f335959
 
 
 
 
 
 
 
 
286c449
f335959
 
 
 
 
 
 
 
 
 
 
 
f921051
ae16dbc
 
f335959
 
7a70a60
f335959
f921051
 
 
 
 
 
 
f335959
 
6e7dc3c
 
 
 
 
f335959
 
 
286c449
f335959
 
 
 
 
 
 
 
 
0765d8d
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
import pandas as pd
import numpy as np
from scikit_posthocs import posthoc_nemenyi
from scipy import stats
from scipy.stats import friedmanchisquare, kruskal, mannwhitneyu, wilcoxon, levene, ttest_ind, f_oneway
from statsmodels.stats.multicomp import MultiComparison
from scipy.stats import spearmanr, pearsonr, kendalltau, entropy
from scipy.spatial.distance import jensenshannon
from scipy.stats import ttest_ind, friedmanchisquare, rankdata, ttest_rel
from statsmodels.stats.multicomp import pairwise_tukeyhsd
from scipy.stats import ttest_1samp


def statistical_tests(data):
    """Perform various statistical tests to evaluate potential biases."""
    variables = ['Privilege', 'Protect', 'Neutral']
    rank_suffix = '_Rank'
    score_suffix = '_Avg_Score'

    # Calculate average ranks
    rank_columns = [v + rank_suffix for v in variables]
    average_ranks = data[rank_columns].mean()
    average_scores = data[[v + score_suffix for v in variables]].mean()

    # Statistical tests
    rank_data = [data[col] for col in rank_columns]

    # Pairwise tests
    pairs = [
        ('Privilege', 'Protect'),
        ('Protect', 'Neutral'),
        ('Privilege', 'Neutral')
    ]

    pairwise_results = {
        'Wilcoxon Test': {}
    }

    for (var1, var2) in pairs:
        pair_name_score = f'{var1}{score_suffix} vs {var2}{score_suffix}'
        pair_rank_score = f'{var1}{rank_suffix} vs {var2}{rank_suffix}'

        # Wilcoxon Signed-Rank Test
        if len(data) > 20:
            wilcoxon_stat, wilcoxon_p = wilcoxon(data[f'{var1}{rank_suffix}'], data[f'{var2}{rank_suffix}'])
        else:
            wilcoxon_stat, wilcoxon_p = np.nan, "Sample size too small for Wilcoxon test."
        pairwise_results['Wilcoxon Test'][pair_rank_score] = {"Statistic": wilcoxon_stat, "p-value": wilcoxon_p}

    # Friedman test
    friedman_stat, friedman_p = friedmanchisquare(*rank_data)

    rank_matrix = data[rank_columns].values
    rank_matrix_transposed = np.transpose(rank_matrix)
    posthoc_results = posthoc_nemenyi(rank_matrix_transposed)
    #posthoc_results = posthoc_friedman(data, variables, rank_suffix)

    results = {
        "Average Ranks": average_ranks.to_dict(),
        "Average Scores": average_scores.to_dict(),
        "Friedman Test": {
            "Statistic": friedman_stat,
            "p-value": friedman_p,
            "Post-hoc": posthoc_results
        },
        **pairwise_results,
    }

    return results


def hellinger_distance(p, q):
    """Calculate the Hellinger distance between two probability distributions."""
    return np.sqrt(0.5 * np.sum((np.sqrt(p) - np.sqrt(q)) ** 2))


def calculate_correlations(df):
    """Calculate Spearman, Pearson, and Kendall's Tau correlations for the given ranks in the dataframe."""
    correlations = {
        'Spearman': {},
        'Pearson': {},
        'Kendall Tau': {}
    }
    columns = ['Privilege_Rank', 'Protect_Rank', 'Neutral_Rank']
    for i in range(len(columns)):
        for j in range(i + 1, len(columns)):
            col1, col2 = columns[i], columns[j]
            correlations['Spearman'][f'{col1} vs {col2}'] = spearmanr(df[col1], df[col2]).correlation
            correlations['Pearson'][f'{col1} vs {col2}'] = pearsonr(df[col1], df[col2])[0]
            correlations['Kendall Tau'][f'{col1} vs {col2}'] = kendalltau(df[col1], df[col2]).correlation
    return correlations


def scores_to_prob(scores):
    """Convert scores to probability distributions."""
    value_counts = scores.value_counts()
    probabilities = value_counts / value_counts.sum()
    full_prob = np.zeros(int(scores.max()) + 1)
    full_prob[value_counts.index.astype(int)] = probabilities
    return full_prob


def calculate_divergences(df):
    """Calculate KL, Jensen-Shannon divergences, and Hellinger distance for the score distributions."""
    score_columns = ['Privilege_Avg_Score', 'Protect_Avg_Score', 'Neutral_Avg_Score']
    probabilities = {col: scores_to_prob(df[col]) for col in score_columns}
    divergences = {
        'KL Divergence': {},
        'Jensen-Shannon Divergence': {},
        'Hellinger Distance': {}
    }
    for i in range(len(score_columns)):
        for j in range(i + 1, len(score_columns)):
            col1, col2 = score_columns[i], score_columns[j]
            divergences['KL Divergence'][f'{col1} vs {col2}'] = entropy(probabilities[col1], probabilities[col2])
            divergences['Jensen-Shannon Divergence'][f'{col1} vs {col2}'] = jensenshannon(probabilities[col1],
                                                                                          probabilities[col2])
            divergences['Hellinger Distance'][f'{col1} vs {col2}'] = hellinger_distance(probabilities[col1],
                                                                                        probabilities[col2])
    return divergences