The air quality index, or AQI, measures how polluted the air is in your city and assigns a number based on the quality of the air. Over 100 is unhealthy.

Given the following quadratic regression equation, estimate the number of days the AQI exceeded 100 in the year 1988.

n = 1.76t^2 - 13.32t + 41.00
(let t represent the number of years since 1990. therefore, t = 0 corresponds the year 1990. round to the nearest whole day.)

A. 60 days
B. 75 days
C. 61 days
D. 21 days

Question

The air quality index, or AQI, measures how polluted the air is in your city and assigns a number based on the quality of the air. Over 100 is unhealthy. 

Given the following quadratic regression equation, estimate the number of days the AQI exceeded 100 in the year 1988. 

n = 1.76t^2 - 13.32t + 41.00
(let t represent the number of years since 1990. therefore, t = 0 corresponds the year 1990. round to the nearest whole day.)

A. 60 days
B. 75 days
C. 61 days
D. 21 days

mertsj · Answer

Well, I said that t = -2 and got 75 days.