Question

Should You Eat Farmed Salmon?

My teacher sent me Statcrunch data file which gives us information collected from a random sample of 150 farmed salmon from different parts of the world. The data was collected in 2004 and the results were published in the prestigious journal Science.

https://www.statcrunch.com/app/index.php?dataid=3432505

The file contains where the salmon was farmed and the level of mirex found in the salmon. Mirex is a banned pesticide that can be cancer-causing. The units for the Mirex are in parts per million (ppm).

Here are the questions I need help with.

1) Create some comparative graphs which show the concentrations of mirex in salmon sorted by location. (Hint: if choose your graph correctly and use the “group by” feature in Statcrunch, you can get these all on one graph.). Paste the statcrunch graph and indicate which regions have lower levels of mirex.

2) Construct a 95% confidence interval to estimate the proportion of farmed salmon which comes from Chile. Include a sentence about the interval.

3) The Environmental Protection Agency’s recommended “screening value” for mirex is 0.08 ppm. Do farm-raised salmon appear to be contaminated beyond the level permitted by the EPA? Using a 5% level of significance, complete a hypothesis test to answer that question. Follow all the steps, include Statcrunch output, and express your decision clearly. Based on your results, would you have concerns about eating farm-raised salmon?

Answer 1

1. The graph is:

2. The 95% confidence interval to estimate the proportion of farmed salmon which comes from Chile is between 0.136 and 0.264.

Observed
0.2	p (as decimal)
30/150	p (as fraction)
30.	X
150	n
0.0408	std. error
0.136	confidence interval 95.% lower
0.264	confidence interval 95.% upper
0.064	margin of error

3. The hypothesis being tested is:

H0: µ = 0.08

Ha: µ ≠ 0.08

0.080000	hypothesized value
0.090127	mean Data
0.049554	std. dev.
0.004046	std. error
150	n
149	df
2.503	t
.0134	p-value (two-tailed)

The p-value is 0.0134.

Since the p-value (0.0134) is less than the significance level (0.05), we can reject the null hypothesis.

Therefore, we can conclude that farm-raised salmon appear to be contaminated beyond the level permitted by the EPA.