píngfāngpíngjūnshù
ㄆㄧㄥˊ ㄈㄤ ㄆㄧㄥˊ ㄐㄩㄣ ㄕㄨˋ
Simplified 平方平均数
Taivo → Settings → Partner inbox → Make the link. It stays in this browser.
Keep 平方平均數 and it comes back until you know it.