半數致死量...請幫忙!

The '50' in the term LD50 (Lethal Dose 50) denotes a probability of 50%. That is, half of the number of affected objects will die if they are fed with a dose of 10 mg of drug for every unit mass of the experimental object.
For example, if an experimental object is of mass, say 10 kg, the LD50 for it will be 10 mg/kg x 10 kg = 100 mg
Looking at another view, if a specific experimental object is fed with the amount of LD50 of drug (i.e. 100 mg for a 10 kg mass object), it will have a chance of 50% dying.

002正解
mg/kg係用實驗值計出黎

比如係用唔同份量既毒藥
餵同等重量既一堆白老鼠

響0%老鼠死晒到100%老鼠死晒之間
我地有唔同既份量對應唔同老鼠既死亡率
只要用依堆數據port條graph
咁你50%死亡率響條graph度過去既藥量（mg）
再除番一隻老鼠既重量（kg）得出黎就係LD50

小補充
實驗用既動物重量係唔可以相差太大既
如果唔係會影響LD50既值
而唔同品種既動物有唔同既LD50
依個係因為唔同動物既代謝系統有分別

所以小鼠LD50未必等於大鼠LD50
同樣地老鼠既LD50亦未必同人類既LD50一樣

應是：
用 10mg 能殺死一公斤實驗物的一半．

如說：殺死半公斤(一公斤的50%)要用10mg呢．會誤會爲用 10mg 便能殺死全部實驗物，而實驗物只有半公斤．