Answer:
158 cases
Explanation:
Given tbe quadratic regression model :
y = -2x^2 + 40x + 8
y = number of cases of a new disease
x = number of years
The predicted number of cases of a new disease in 15 years can be calculated thus ;
Put x = 15 in the equation ;
y = -2(15)^2 + 40(15) + 8
y = - 2 * 225 + 600 + 8
y = - 450 + 600 + 8
y = 158
158 cases