Question

A food safety guideline is that the mercury in fish should be below 1 part per million​ (ppm). Listed below are the amounts of mercury​ (ppm) found in tuna sushi sampled at different stores in a major city. Construct a 98​% confidence interval estimate of the mean amount of mercury in the population. Does it appear that there is too much mercury in tuna​ sushi? 0.52  0.79  0.11  0.87  1.35  0.57  0.89

Answer 1

solution:-

given that 0.52,0.79,0.11,0.87,1.35,0.57,0.89

mean = 0.7286

standard deviation s = 0.3846

n = 7

degree of freedom df = n-1 = 7 - 1 = 6

the value of 98% confidence from t table is t = 3.143

confidence interval formula

=> mean +/- t * s/sqrt(n)

=> 0.7286 +/- 3.143 * 0.3846/sqrt(7)

=> 0.272 < µ < 1.185

Does it appear that there is too much mercury in tuna​ sushi?

=> yes, because it is possible that the mean is not greater than 1 ppm Also, at least one of the sample values exceeds 1 ppm, so at least some of the fish have too much mercury