数据：2022.01.01--2024.09.01 全部的random PK pair

数据： period: 20230101 to 2024010 条件：选择前一年有超过20次invite PK的主播，在2023年的invite PK数据

In this analysis, I examine the statistical significance of attitude changes towards various political objects before and after the MLK assassination, stratified by race. Using the dataset of affect percentages and sample sizes reported in the article, I perform chi-squared tests on contingency tables to assess significant shifts in positive and negative attitudes for each political object and racial group. The results are presented in tables and visualized through bar charts, highlighting statistically significant changes (p < 0.05). Additionally, I conduct polarization analyses using both variance-based methods (Levene’s test) and more advanced techniques (polarization index, kurtosis, and Kolmogorov-Smirnov tests) to examine changes in the spread and shape of attitude distributions. For significant changes, I create density ridge plots to visualize the shifts in attitude distributions. This approach combines methods available in 1969 with modern techniques to provide a comprehensive view of attitude changes and potential polarization effects following the assassination. The findings regarding the minimal effect on white respondents are largely aligned with Hofstetter’s article. No statistically significant changes in positive or negative affect were observed among white respondents for any political object. The advanced polarization analysis confirms this, showing no significant changes in the distribution of white attitudes (all KS p-values = 1). For Black respondents, the most notable change was towards the police. This change manifested in multiple ways: a significant increase in negative affect (from 3.7% to 31.0%, p = 0.01), a substantial but not statistically significant decrease in positive affect (from 88.9% to 58.6%, p = 0.274), a significant increase in opinion polarization as measured by variance ratio (2.450, p < 0.01), and a significant change in the overall distribution of attitudes (KS p-value = 0.0154). The polarization for police attitudes among Black respondents increased dramatically indicating a substantial increase in polarization. Other changes in Black respondents’ attitudes were observed but were not statistically significant.

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