Biology and Environmental Science
In August 2013, Vancouver Coastal Health warned swimmers that the coliform count at East False Creek was approximately twice the safe level.15 The contamination was attributed to boats, birds, geese, and warm weather. A random sample of locations along the creek was obtained, and the coliform count (bacteria per 100 ml of water) was measured in early August and again following several rain storms.
a. What is the common characteristic that makes these data paired?
b. Use a one-sided paired t test to determine whether the rain caused a decrease in the coliform count. Assume normality and use a = 0.001.
c. Find the safe level of coliform. Do you think it was safe to swim in the creek after the rain? Why or why not?