Please help! 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 22 ug/m3 (micrograms per cubic meter). If 144 readings
were taken, and the standard deviation of the sample measurements was
4 ug/m3, you are 99.7% confident that actual concentration of fine
particulates at the school is
A. 21 ug/m3 - 23 pg/m3
B. 18 ug/m3 - 26 pg/m3
C. 21.7 ug/m3 - 22.3 pg/m3
D. 21.3 pg/m3 - 22.7 ug/m3