Mathematics, 21.03.2020 10:24 starfox5454
Keeping water supplies clean requires regular measurement of levels of pollutants. The measurements are indirect- a typical analysis involves forming a dye by a chemical reaction with the dissolved pollutant, then passing light through the solution and measuring its " absorbence." To calibrate such measurements, the laboratory measures known standard solutions and uses regression to relate absorbence and pollutant concentration. This is usually done every day. Here is one series of data on the absorbence for different levels of nitrates. Nitrates are measured in centigrams per liter of water.
Nitrates 10 7 15 30 20 60 60 100 140 320
Absorbance 5 7 10 25 40 90 130 190 230 220
Chemical theory says that these data should lie on a straight line. If the correlation is not at least 0.997, something went wrong and the calibration procedure is repeated.
(a) Find the correlation r.
r =
(b) Must the calibration be done again? (Answer YES or NO).
Answers: 2
Mathematics, 21.06.2019 20:30
Barbara has a good credit history and is able to purchase a car with a low-interest car loan. she co-signs a car loan for her friend jen, who has poor credit history. then, jen defaults on the loan. who will be held legally responsible by the finance company and why? select the best answer from the choices provided. a. barbara will be held legally responsible because she has a good credit history. b. jen will be held legally responsible because she drives the car. c. barbara will be held legally responsible because she is the co-signer. d. jen will be held legally responsible because she has a poor credit history. the answer is a
Answers: 3
Keeping water supplies clean requires regular measurement of levels of pollutants. The measurements...
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