if possible, please show me how to do these using excel

The oral acute toxicity of a newly synthesized chemical is unknown. A preliminary experiment is conducted to determine the acute oral toxicity in one species of test animals. The mean response of the test subjects was calculated at each dose level and is given below. Assume for simplicity that each of the rats is very close to 200g in weight. a. Calculate the dose (expressed as mg/kg ) for each group. b. Plot cumulative percent ( y-axis) versus dose ( x-axis). c. Obtain/estimate the LOEL, LD10,LD50,LD90 and NOEL (if any). d. Can a threshold dose be determined from this data; if so, what is the threshold dose in mg/kg ? If a threshold cannot be directly determined, briefly explain