7.

The U.S. Center for Disease Control (CDC) collects anthropometric (weight, height etc..) data on large samples of US youth, both male and female, and uses these data to create growth charts, which essentially characterize the distributions of these measures by age and sex. For example, for 18 years old males, the mean body mass index (BMI) is 21.9 (kg/m²) with a standard deviation (SD) of 3.2 (kg/m²). Physicians (and patients) can use these data to figure out how individual BMI values compare relative to the age and sex specific distribution. Suppose you are a physician and you are screening patients at a health fair.You may assume the distribution of BMI values for 18 year-old males is a normal distribution.

- Estimate a range of "normal" BMI values, ie: a range that contains the middle 95% of the values in the population of 18 year old males.

a. (15.5, 28.3)

b. (17.1, 26.7)

c. (13.9, 29.9)

d. (19.5, 22.7)

10

The U.S. Center for Disease Control (CDC) collects anthropometric (weight, height etc..) data on large samples of US youth, both male and female, and uses these data to create growth charts, which essentially characterize the distributions of these measures by age and sex. For example, for 18 years old males, the mean body mass index (BMI) is 21.9 (kg/m²) with a standard deviation (SD) of 3.2 (kg/m²). Physicians (and patients) can use these data to figure out how individual BMI values compare relative to the age and sex specific distribution. Suppose you are a physician and you are screening patients at a health fair.

-Not surprisingly, perhaps, the actual distribution of BMI values among 18 year old males is right skewed (slightly, not heavily so). Given this fact, what additional summary statistics would be necessary to properly estimate the interval in question 17?

A. median

B. 5th and 90th percentiles

C. 2.5th and 97.5th percentiles

D. 25th and 75th percentiles