A small amount of the trace element selenium, 50-200 micrograms (g) per day, is considered essential to good health. Suppose that random samples ofn₁=n₂=20

adults were selected from two regions of the United States and that a day's intake of selenium was recorded for each person. The mean and standard deviation of the selenium daily intakes for the20adults from region 1 werex₁=167.8

ands₁=23.2g,

respectively. The corresponding statistics for the20adults from region 2 werex₂=140.8

ands₂=17.4g.

Find a 95% confidence interval for the difference(₁₂)

in the mean selenium intakes for the two regions. (Round your answers to three decimal places.)

__ g to__g

Interpret this interval.

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.

In repeated sampling, 5% 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.