sampling with unequal probability的意思|示意
美 / ˈsæmplɪŋ wið ʌnˈi:kwəl ˌprɔbəˈbiliti /
英 / ˈsæmplɪŋ wɪð ʌnˈikwəl ˌprɑbəˈbɪlɪti /
不等概率抽样