A small amount of the trace element selenium, 50â200 micrograms (μg) per day, is considered essential to good health. Suppose that random samples of
n1 = n2 = 40 adults
were selected from two regions of Canada and that a day's intake of selenium, from both liquids and solids, was recorded for each person. The mean and standard deviation of the selenium daily intakes for the 40 adults from region 1 were
x1 = 167.8
and
s1 = 24.5 μg,
respectively. The corresponding statistics for the 40 adults from region 2 were
x2 = 140.9
and
s2 = 17.3 μg.
Find a 95% confidence interval for the difference
(μ1 â μ2)
in the mean selenium intakes for the two regions. (Round your answers to three decimal places.)
μg to μg
Interpret this interval.
In repeated sampling, 5% of all intervals constructed in this manner will enclose the difference in population means.There is a 95% chance that the difference between individual sample means will fall within the interval. 95% of all differences will fall within the interval.In repeated sampling, 95% of all intervals constructed in this manner will enclose the difference in population means.There is a 5% chance that the difference between individual sample means will fall within the interval.