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In: Statistics and Probability

Ecologists periodically measure the concentration of coliform bacteria at an urban reservoir. Each time, water samples...

Ecologists periodically measure the concentration of coliform bacteria at an urban reservoir. Each
time, water samples are taken from various random locations within the reservoir. The distribution
of bacteria counts in the past has followed a normal distribution with a mean of 2.8 ppm (parts per
million). In the latest set of readings, the mean count for the 27 water samples was 2.98 ppm with an
s.d. of 0.455 ppm. Thus there is some evidence that the bacteria concentration in the reservoir has
increased.
a. Set up hypotheses for testing whether the bacteria concentration in the reservoir has increased.

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orchestra answered 2 years ago
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