The city of Fairview runs a swim league for teens aged 13 to 17. Suppose a swimmer from the league is randomly selected. Let X be the age (in years) of the selected swimmer. Here is the probability distribution of X. Value x of X 13 14 15 16 (a) Older than 15: (b) 14 or younger: 0 17 0.28 0.21 0.18 0.18 0.15 P(X=x) For parts (a) and (b) below, find the probability that the randomly selected swimmer has the age described. X S

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Arsenic is a compound that occurs naturally in very low concentrations. Arsenic blood concentrations in healthy individuals are Normally distributed with a mean of 3.2 mg/dl. Some areas of the United States have naturally elevated arsenic levels in the ground and water supplies. Researchers took a sample 20 water samples from a particular area and measured the arsenic levels in each of the 20 water samples. They want to determine if there is sufficient evidence to conclude that the arsenic level in that area is higher than 3.2 mg/dl. hypothesis test for one population mean (unknown population standard deviation) confidence interval estimate for one population mean (unknown population standard deviation) hypothesis test for population mean from paired differences confidence interval estimate for population mean from paired differences hypothesis test for difference in population means from two independent samples confidence interval estimate for difference in population means from two…

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