Solve the problem.In one study, a type of fish was exposed to a toxin. The table lists toxin concentrations in the fish after a certain number of hours. The concentration C of the toxin in the fishes' bloodstream was measured in micrograms of toxin per gram of fish after x hours of exposure. (i) Describe the relationship between x and C; (ii) Use regression to find a cubic polynomial function f(x) that models the data; (iii) graph C and the data; (iv) Concentrations above 30 are lethal to the fish. Determine how many hours of exposure it takes for this to occur.

Question

A. (i) As x increases, C increases; 
(ii) f(x) ? 0.38x³ - 4.35x² + 22.97x - 33.40
(iii)
 
(iv) x ? 6.0 (approximately)
B. (i) As x increases, C increases; 
(ii) f(x) ? 0.28x³ - 4.35x² + 24.97x - 33.40
(iii)
 
(iv) x ? 7.9 (approximately)
C. (i) As x increases, C increases; 
(ii) f(x) ? 0.28x³ - 5.35x² + 22.97x - 33.40
(iii)
 
(iv) x ? 6.2 (approximately)
D. (i) As x increases, C increases; 
(ii) f(x) ? 0.38x³ - 5.35x² + 24.97x - 33.40
(iii)
 
(iv) x ? 9.1 (approximately)

Answer 1

Answer: B