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?

0.56, 0.77, 0.11, 0.93, 1.23, 0.50, 0.86

What is the confidence interval estimate of the population mean μ​?

_ ppm < μ < _ ppm

Answer 1

Confidence interval for Population mean is given as below:

Confidence interval = Xbar ± t*S/sqrt(n)

From given data, we have

Xbar = 0.708571429

S = 0.358581863

n = 7

df = n – 1 = 6

Confidence level = 98%

Critical t value = 3.1427

(by using t-table)

Confidence interval = Xbar ± t*S/sqrt(n)

Confidence interval = 0.708571429 ± 3.1427*0.358581863/sqrt(7)

Confidence interval = 0.708571429 ± 0.4259

Lower limit = 0.708571429 - 0.4259 = 0.2826

Upper limit = 0.708571429 + 0.4259 = 1.1345

Confidence interval = (0.2826, 1.1345)

0.2826 ppm < µ < 1.1345 ppm