A Study Conducted by the National Center for Health Statistics

Multiple Choice

A study conducted by the National Center for Health Statistics as part of the Center for Disease Control and Prevention (CDC) found that, as of 2015-2016, 39.6% of Americans over the age of 20 fit the medical definition of being obese (BMI of 30 or higher) . A city known for its plentiful outdoor opportunities believes that number is lower among its residents. A representative sample of 80 city residents is collected and the BMI calculated for each (based on reported height and weight) . The variable of interest is whether the resident fit the medical definition of obese. The study found 22 people in the sample fit the medical definition of obese.
-The standardized statistic is equal to -2.213. Interpret this value in the context of the problem.

A) On average, each simulated sample proportion of residents that fit the medical definition of obese is 2.213 standard deviations away from 0.396.
B) The probability of obtaining a sample proportion of 0.275 or something more extreme, assuming 39.6% of all city residents fit the medical definition of obese, is 0.02213.
C) The observed sample proportion of city residents that fit the medical definition of obese, 0.275, is 2.213 standard deviations below the hypothesized proportion 0.396.
D) The hypothesized proportion of city residents that fit the medical definition of obese, 0.396, is 2.213 standard deviations below the sample proportion 0.275.