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?

Sarah took the advertising department from her company on a round trip to meet with a potential client. including sarah a total of 11 people took the trip. she was able to purchase coach tickets for $280 and first class tickets for $1280. she used her total budget for airfare for the trip, which was $6080. how many first class tickets did she buy? how many coach tickets did she buy?

Which of the following circles have their centers on the x-axis? check all that apply.

Using only the digits 5, 6, 7, 8, how many different three digit numbers can be formed if no digit is repeated in a number?