Question

The Water Department checks the city water supply on a regular basis for contaminants such as trihalomethanes (THMs). The Water Department takes 200 samples and estimates that the concentration of THMs in your drinking water is 3 ppb (parts per billion), with a standard deviation of 0.3 ppb.

Assuming the samples were random and unbiased, how much confidence can you have in this data?

Answer 1

A. 95% confident the average concentration of PCBs in the water supply is between 2.4 ppb and 3.6 ppb.
B. 97% confident the average concentration of PCBs in the water supply is between 2.6 ppb and 3.8 ppb.
C. 99.7% confident the average concentration of PCBs in the water supply is between 2.7 ppb and 3.3 ppb.
D. 68% confident the average concentration of PCBs in the water supply is between 2.9 ppb and 3.1 ppb.

Answer 2

witch do you think it is

Answer 3

I have no idea

Answer 4

lol um whats thms?

Answer 5

Good question