students in a statistics class take a random sample of 100 students at their college and record how many units each student is enrolled in. the students compute a 90% confidence interval for the mean number of units for students at their college and get (11.93, 12.47).

The smokey mountains have over 2,100 miles of rushing mountain streams and rivers that flow through the park. in each mile lives a diverse community of native fish, amphibians, insects, and larvae, some of which are found only in the southern appalachians. park managers and scientific researchers test many factors such as fish populations, the watersheds and water tests to determine a) too many lizards are present b) the water quality of the stream c) rainwater is running into local streams d) if visitors to the park are overstaying their welcome