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Paving stones: 175 paving stones were examined for cracks, and 18 were found to be cracked. The same 175 stones were examined for discoloration, and 15 were found to be discolored. A total of 7 stones were both cracked and discolored. One of the 175 stones is selected at random. Round all answers to four decimal places. (d) Find the probability that it is cracked or discolored. The probability that it is cracked or discolored is l l. Dirty air: The federal government has enacted maximum allowable standards for air pollutants such as ozone. Let A be the number of days per year that the level of air pollution exceeds the standard in a certain city. The probability distribution of X is given by X 0 2 3 4 P(x 0.34 0.39 0.19 0.05 0.03(d) Find the probability that the standard is exceeded on more than two days. The probability that the standard is exceeded on more than two days is i i. Google it: According to a recent report, 67% of Internet searches in a particular month used the Google search engine. Assume that a sample of 25 searches is studied. Round the answers to at least four decimal places. (d) Would it be unusual if fewer than 13 used Google? Use a cutoff of 0.05. It (Choose one) V be unusual if fewer than 13 used Google since the probability is l l. College bound: A national college researcher reported that 66% of students who graduated from high school in 2012 enrolled in college. Twenty eight high school graduates are sampled. Round the answers to four decimal places. (d) Would it be unusual if more than 23 of them enroll in college? It (Choose one) V be unusual if more than 23 of them enroll in college since the probability is l l. Tree heights: Cherry trees in a certain orchard have heights that are normally distributed with mean p=111 inches and standard deviation 0': 13 inches. Use the Excel spreadsheet to answer the following. Round the answers to at least two decimal places. (c) An agricultural scientist wants to study the tallest 2% of the trees to determine whether they have a certain gene that allows them to grow taller. To do this, she needs to study all the trees above a certain height. What height is this? The agricultural scientist should study all the trees above ' I inches. X