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Systolic blood pressures are approximately Normal with a mean of 120 and a standard deviation of 8 . a. What percentage of people have a systolic blood pressure above \(130 ?\) b. What is the range of systolic blood pressures for the middle \(60 \%\) of the population? c. What percentage of people have a systolic blood pressure between 120 and \(130 ?\) d. Suppose people with systolic blood pressures in the top \(15 \%\) of the population have their blood pressures monitored more closely by health care professionals. What blood pressure would qualify a person for this additional monitoring?

The distribution of spring high temperatures in Los Angeles is approximately Normal, with a mean of 75 degrees and a standard deviation of \(2.5\) degrees. a. What is the probability that the high temperature is less than 70 degrees in Los Angeles on a day in spring? b. What percentage of Spring day in Los Angeles have high temperatures between 70 and 75 degrees? c. Suppose the hottest spring day in Los Angeles had a high temperature of 91 degrees. Would this be considered unusually high, given the mean and the standard deviation of the distribution? Why or why not?

According to the Pew Research Center, \(73 \%\) of Americans have read at least one book during the past year. Suppose 200 Americans are randomly selected. a. Find the probability that more than 150 have read at least one book during the past year. b. Find the probability that between 140 and 150 have read at least one book during the past year. c. Find the mean and the standard deviation for this binomial distribution. d. Using your answer to part c, complete this sentence: It would be surprising to find that fewer than \(-\) people in the sample had read at least one book in the last year.

The distribution of the math portion of SAT scores has a mean of 500 and a standard deviation of 100 , and the scores are approximately Normally distributed. a. What is the probability that one randomly selected person will have an SAT score of 550 or more? b. What is the probability that four randomly selected people will all have SAT scores of 550 or more? c. For 800 randomly selected people, what is the probability that 250 or more will have scores of 550 or more? d. For 800 randomly selected people, on average how many should have scores of 550 or more? Round to the nearest whole number. e. Find the standard deviation for part d. Round to the nearest whole number. f. Report the range of people out of 800 who should have scores of 550 or more from two standard deviations below the mean to two standard deviations above the mean. Use your rounded answers to part d and e. g. If 400 out of 800 randomly selected people had scores of 550 or more, would you be surprised? Explain.

Babies in the United States have a mean birth length of \(20.5\) inches with a standard deviation of \(0.90\) inch. The shape of the distribution of birth lengths is approximately Normal. a. How long is a baby born at the 20 th percentile? b. How long is a baby born at the 50 th percentile? c. How does your answer to part b compare to the mean birth length? Why should you have expected this?