The output from a sewage treatment plant is constantly monitored to assess treatment efficacy. Suppose that the mean coliform content is 20 bacteria/ml with a standard deviation of 4
bacteria/ml. An automatic measuring device is being used to monitor the bacterial levels. An alarm
should ring whenever the bacterial level exceeds the 97.5th percentile. The upper bound should be:
O 28 per ml
20 per ml
32 per m
O None of the other answers are correct
O 16 per ml
O 24 per ml