ABC Textiles, Inc. has a textile production facility located in Palm City, FL. It lies along a river that is used for drinking water for the surrounding town and is therefore tested regularly for chemical contaminants according to EPA standards. There is also a recreational beachfront with swimming and boating located ½ mile downstream of the plant. Over the last ten years, the incidence of a skin reaction called allergic dermatitis has increased dramatically for swimmers at the recreational beachfront.
Due to public concern, the local water utility began checking for elevated levels of several pollutants that cause skin reactions. Over the course of a year, they collected 45 water samples from a location adjacent to the output of the industrial plant. These samples were tested and elevated levels of chromium were identified. The EPA’s Maximum Contaminant Level (MCL) for chromium is 0.1 mg/L. With the knowledge that chromium pollution can result from fabric dyeing within textile factories, a group of concerned citizens has brought a class-action lawsuit against ABC Textiles, Inc. The class claims that the company’s textile mill has contributed to elevated chromium levels in the river, causing skin reactions at the local beach.
Due to the significance of this litigation, the Judge involved with the case, The Honorable Orlana Leia, has brought you in as an expert witness, independent of either side of the litigation, to give your expert opinion on the chromium exceedance. At your request, she is providing you with data from the 45 samples the water utility collected. She has requested that you analyze whether the chromium levels in the river exceed the EPA standard. Because there are no other outputs to the river within 5 miles, it can be presumed that the textile plant is the most likely source of elevated chromium levels, if they are present in the river. The area between the output of the industrial plant and the beachfront is populated with residential housing, and the prosecution and defense have agreed that illegal dumping or another source of contamination in this area is highly unlikely.
She is requiring that you complete your work with a high level of confidence, therefore you have suggested using a significance level of .01 (i.e., 99% confidence). You are to provide the jury with which side of the litigation you would support and why in a written document that makes the determination clear and believable to them. The document you are to provide is to follow the court’s template and their Legal memorandum guide. You will also copy the document to John Coltrane, Clerk of the Courts, Mitchell Bilano, Plaintiffs’ Counsel, and Jill Gailow, Defendant’s Counsel. Remember that you are only an expert on statistical analysis of the exceedance of chromium in the river, not on whether elevated chromium can cause allergic dermatitis. Be careful not to overstate your findings – don’t make any assumptions that aren’t very clearly suggested by the data. (Data File Download Data File)
Sample Date
Sample Number
Chromium Level (mg/L)
1-Aug
1
0.094
7-Aug
2
0.08
20-Aug
3
0.077
28-Aug
4
0.081
5-Sep
5
0.086
13-Sep
6
0.078
20-Sep
7
0.117
29-Sep
8
0.084
3-Oct
9
0.113
10-Oct
10
0.094
27-Oct
11
0.088
5-Nov
12
0.093
12-Nov
13
0.115
26-Nov
14
0.121
1-Dec
15
0.112
8-Dec
16
0.119
15-Dec
17
0.11
21-Dec
18
0.101
29-Dec
19
0.082
4-Jan
20
0.088
11-Jan
21
0.084
19-Jan
22
0.094
25-Jan
23
0.118
31-Jan
24
0.127
7-Feb
25
0.123
14-Feb
26
0.096
22-Feb
27
0.093
1-Mar
28
0.112
8-Mar
29
0.071
18-Mar
30
0.081
31-Mar
31
0.082
5-Apr
32
0.092
10-Apr
33
0.088
19-Apr
34
0.081
25-Apr
35
0.076
1-May
36
0.079
9-May
37
0.08
18-May
38
0.91
25-May
39
0.082
1-Jun
40
0.072
12-Jun
41
0.071
25-Jun
42
0.075
2-Jul
43
0.092
16-Jul
44
0.102
24-Jul
45
0.106