卡方檢定統計量

R 中的類別資料推論

Andrew Bray

Assistant Professor of Statistics at Reed College

比較長條圖

已填色的國防支出長條圖

已填色的國防軍備長條圖

假設檢定

null <- data %>%
  specify(var1 ~ var2) %>%
  hypothesize(null = "independence") %>%
  generate(reps = 100, type = "permute") %>%
  calculate(stat = ?)

選擇統計量

兩個長條圖

選擇統計量

三個長條圖

選擇統計量

observed_counts

             party
natspac       Dem Ind Rep
  TOO LITTLE    8  13   9
  ABOUT RIGHT  22  37  17
  TOO MUCH     13  22   8

expected_counts

             party
natspac        Dem  Ind  Rep
  TOO LITTLE   8.7 14.5  6.8
  ABOUT RIGHT 21.9 36.7 17.3
  TOO MUCH    12.4 20.8  9.8

堆疊長條圖：國防支出

選擇統計量

observed_counts

             party
natspac       Dem Ind Rep
  TOO LITTLE    8  13   9
  ABOUT RIGHT  22  37  17
  TOO MUCH     13  22   8

expected_counts

             party
natspac        Dem  Ind  Rep
  TOO LITTLE   8.7 14.5  6.8
  ABOUT RIGHT 21.9 36.7 17.3
  TOO MUCH    12.4 20.8  9.8

(observed_counts - expected_counts) ^ 2

             party
natspac         Dem   Ind   Rep
  TOO LITTLE  0.433 2.240 4.641
  ABOUT RIGHT 0.005 0.076 0.117
  TOO MUCH    0.349 1.492 3.284

sum((observed_counts - expected_counts) ^ 2)

12.63565

卡方距離

註解的三個長條圖

一起來練習吧！

R 中的類別資料推論