Applied Biostatistics for the Health Sciences. Richard J. Rossi
in the United States follows a normal distribution with mean 7.5 pounds and standard deviation 0.5 pounds. Determine theprobability that a full-term baby born in the United States weighs between 7 and 8 pounds.probability that a full-term baby born in the United States weighs more than 9 pounds.probability that a full-term baby born in the United States weighs less than 6.8 pounds.5th percentile of the weights of full-term babies born in the United States.95th percentile of the weights of full-term babies born in the United States.
55 2.55 According to the National Health Statistics Report Number 122, December 20, 2018 (Fryar, 2018), the estimated mean weight of an adult male in the United States is 197.8 pounds. Suppose the distribution of weights of adult males in the US is normally distributed with mean weight µ = 200 pounds with standard deviation of σ = 25 pounds. Determine theprobability that an adult male in the US weighs more than 240 pounds.probability that an adult male in the US weighs less than 140 pounds.probability that an adult male in the US weighs between 180 and 220 pounds.90th percentile of the weights of adult males in the US.
56 2.56 According to the National Health Statistics Report Number 122, December 20, 2018 (Fryar, 2018), the estimated mean body mass index (BMI) of an adult female in the United States is 29.6. Suppose the distribution of BMI values for adult females in the US is normally distributed with mean BMI µ = 30 with standard deviation of σ = 4. Determine theprobability that an adult female in the US has BMI less than 25.probability that an adult female in the US has BMI more than 36.probability that an adult female in the US has BMI between 26 and 32.10th percentile of the BMI values of adult females in the US.
57 2.57 What are the units of a z score?
58 2.58 How many standard deviations below the mean does a z score of −3 correspond to?
59 2.59 Under what conditions is it possible to determine the percentile associated with an observed z score?
60 2.60 Table 2.18 contains the standard weight classifications based on body mass index (BMI) values. Assuming that BMI is approximately normally distributed, determine the z score corresponding to the cutoff for theTable 2.18 The Standard Weight Classifications Based on BMI ScoresWeight ClassificationBMI Percentile RangeUnderweightLess than 5th percentileHealthy weightBetween 5th and 85th percentilesAt risk of overweightBetween 85th and 95th percentilesOverweightGreater than the 95th percentileunderweight classification.healthy classification.at-risk-of-overweight classification.overweight classification.
61 2.61 Because a BMI value for a child depends on age and sex of the child, z scores are often used to compare children of different ages or sexes. Table 2.19 gives the mean and standard deviation for the distribution of BMI values for male children aged 10 and 15. Use the information in Table 2.19 to answer the following questions concerning two male children, a 10 and a 15 years old, each having a BMI value of 25:Table 2.19 The Mean and Standard Deviations of BMI for 10- and 15-year-old Male ChildrenBMIAgeMeanSD1016.62.31519.83.1Compute the z score for the 10-year-old.Compute the z score for the 15-year-old.Which child has a larger BMI value relative to the population of males in their age group?
62 2.62 According to the National Health Statistics Report Number 122, December 20, 2018 (Fryar, 2018), the estimated mean height of an adult male in the United States is 69 inches and the mean height of an adult female in the United States is 63.6 inches. Suppose the standard deviation of the heights of adult males in the US is σm=3.5 and the adult females in the US is σf=2.5. Determinethe z score associated with an adult male in the US who is 74 inches tall.the z score associated with an adult female in the US who is 70 inches tall.the probability that an adult male in the US is taller than 74 inches. Assume the weights are normally distributed.whether the 74 inch male or the 70 inch female is farther above the mean of their respective population.
63 2.63 In which study designs can therelative risk be computed?odds ratio be computed
64 2.64 In a prospective study on melanoma and the risk factor fair complexion, the probability that an individual will have a melanoma in their life given they have a fair complexion is 0.12, and the probability that an individual will have a melanoma in their life given they do not have a fair complexion is 0.05.Compute the relative risk of developing a melanoma for the risk factor fair complexion.Interpret the relative risk.Compute the odds ratio for developing a melanoma for the risk factor fair complexion.Interpret the odds ratio.
65 2.65 In a prospective study on gum disease, group of 50 subjects will receive an oral wash treatment and a control group of 50 subjects will receive a placebo wash. Suppose four subjects in the treatment group developed gum disease and 16 in the control group developed gum disease.Determine the relative risk of developing gum disease for an individual who receives the treatment.Interpret the relative risk.
66 2.66 In a retrospective study of the health problems associated with smoking, a researcher is interested in the relationship between chronic obstructive pulmonary diseases (COPD) and the risk factor smokes. Use the probabilities in Table 2.66 to answer the following questions.COPDRisk FactorYesNoSmokes0.140.86Does not Smoke0.040.96Compute the odds of having COPD for smokers.Compute the odds of having COPD for non-smokers.Compute the odds ratio for COPD and the risk factor smokes.Interpret the odds ratio.Why is it inappropriate to compute the relative risk in this study?
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