For a group experiment, your science class measured the fine-particulate concentrations in the air at random places around campus, and estimated a sample average of 12 μg/m3 (micrograms per cubic meter). If 196 readings were taken, and the standard deviation of the sample measurements was 3.5 μg/m3, you are 99.7% confident that actual concentration of fine particulates at the school is __________ .
a. 1.5g/m^3 - 22.5 g/m^3
b. 5 g/m^3 - 19g/m^3
c. 11.5 g/m^3 - 12.5 g/m^3
d. 11.25 g/m^3 - 12.75 g/m^3

Question

For a group experiment, your science class measured the fine-particulate concentrations in the air at random places around campus, and estimated a sample average of 12 μg/m3 (micrograms per cubic meter). If 196 readings were taken, and the standard deviation of the sample measurements was 3.5 μg/m3, you are 99.7% confident that actual concentration of fine particulates at the school is __________ .
a. 1.5g/m^3 - 22.5 g/m^3
b. 5 g/m^3 - 19g/m^3
c. 11.5 g/m^3 - 12.5 g/m^3
d. 11.25 g/m^3 - 12.75 g/m^3