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?

0.55  0.81  0.09  0.89  1.34  0.49  0.94

__ ppm < μ < __ ppm

(Round to three decimals as needed).

Answer 1

Sample mean = = 0.73

Sample standard deviation = S = [ (X² - n²) / n-1 ] = 0.3975

t critical value at 0.02 level with 6 df = 3.143

98% confidence interval for is

- t * S / sqrt(n) < < + t * S / sqrt(n)

0.73 - 3.143 * 0.3975 / sqrt(7) < < 0.73 + 3.143 * 0.3975 / sqrt(7)

0.258 < < 1.202

98% CI is (0.258 , 1.202 )

There are some values in confidence interval are greater than 1. so it is possible that

there is too much mercury in tuna​ sushi.