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 99%confidence interval estimate of the mean amount of mercury in the population. Does it appear that there is too much mercury in tuna​ sushi?

0.62, 0.71, 0.10, 0.93, 1.32, 0.56, 0.80

what is the confidence interval estimate of the population mean ?

Answer 1

= (0.62 + 0.71 + 0.10 + 0.93 + 1.32 + 0.56 + 0.8)/7 = 0.72

s = sqrt(((0.62 - 0.72)^2 + (0.71 - 0.72)^2 + (0.10 - 0.72)^2 + (0.93 - 0.72)^2 + (1.32 - 0.72)^2 + (0.56 - 0.72)^2 + (0.8 - 0.72)^2)/6) = 0.3721

At 99% confidence interval the critical value is t_0.005,6 = 3.708

The 99% confidence interval for population mean is

+/- t_0.005,6 * s/

= 0.72 +/- 3.708 * 0.3721/

= 0.72 +/- 0.5215

= 0.1985, 1.2415