Help me with this problem please

Question

The average adult Indian Rhino weighs 4600 pounds with a standard deviation of 500 pounds.

a) What percent of Indian Rhinos are more than 4000 pounds?

b) Rhinos in the 80th percentile are called Mega-Rhinos. At what weight does this distinction begin?

 

Answer 1

Prob ( X<4000) = Prob ( z < (4000-4600)/500)

 

                       = Prob( z < -600/500) = Prob ( z < -1.2) = 0.1151 = 11.51%

 

 

 

B)   Prob( Z = z) = 0.8 ----> z=0.85

 

         0.85 = (X-4600)/500 -----> X = 0.85*500+4600 = 5025