The body mass index (BMI) measures body size in people by dividing weight (in pounds) by the square of height (in inches) and then multiplying by a factor of 703. A BMI less than 18.5 is defined as underweight; between 18.5 to 24.9 is normal; between 25 and 29.9 is overweight; and 30 or more is obese. It is well established that Americans have become heavier during the last half century. Assume that the positively skewed distribution of BMIs for adult American males has a mean of 28 with a standard deviation of 4.
(a) Would the median BMI score exceed, equal, or be exceeded by the mean BMI score of 28?
Answer:
Mean exceeds median
(b) What z score defines overweight
Answer:
-0.75
(c) What z score defines obese. Answers on page 427.
0.50
