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 95% confidence interval estimate of the mean amount of mercury in the population. Does it appear that there is too much mercury in tuna​ sushi?

0.58, 0.71, 0.10, 0.86, 1.38, 0.56, 0.85 

What is the confidence interval estimate of the population mean(μ) _____<μ<_____​?

Answer 1

From sample data,

= X / n = 0.72

S = sqrt [ X2 - n2 / ( n -1) ] = 0.3877

df = n - 1 = 7- 1 = 6

From T table,

t critical value at 0.05 level with 6 df = 2.447

95% Confidence interval is

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

0.72 - 2.447 * 0.3877 / sqrt ( 7) < < 0.72 + 2.447 * 0.3877 / sqrt ( 7)

0.361 < < 1.079