An ecological group suspects tuna are consuming dangerous levels of copper in a region of the world. Dangerous levels of copper are classified when they reach beyond 5.7 parts per million. A random sample of 21 tunas in the region were tested and the data is shown in the stemplot.
Copper Levels
20
2.
31
3578
4 01
45678
5 | 0233
5689
634
6
Key: 20 = 2.0 parts per million
Part A: What proportion of the tuna in the sample have dangerous levels of copper in their systems? (4 points)
Part B: Construct and interpret a 98% confidence interval for the mean copper levels of the tuna if the sample of 21 tuna has a mean copper level of 4.77 parts per million and standard
deviation of 11 16 parts per million. (6 points)