题目三个样本率比较时的自由度为A. 3-1B. (R-1)(C-1)C. n-1D. 2三个样本率比较时的自由度为A. 3-1B. (R-1)(C-1)C. n-1D. 2题目解答答案BDB. (R-1)(C-1)D. 2