Final answer:
The correct answer to the question "The ___ rate is calculated as the number of cases in a given time divided by the population at risk" is b) Incidence. Incidence rate measures the number of new cases of a disease, while morbidity refers to the state of illness or disease prevalence in the population.
Step-by-step explanation:
The rate calculated as the number of cases in a given time divided by the population at risk is known as the incidence rate. Contagious diseases such as influenza typically have a high incidence rate because each infected individual has the potential to transmit the disease to several others. The first 'M' in MMWR, which stands for Morbidity and Mortality Weekly Report, refers to morbidity, not incidence. The MMWR is a publication by the Centers for Disease Control and Prevention (CDC) that provides epidemiological data.
In terms of the options provided in the question, a) Mortality is the number of deaths due to a disease, b) Incidence is the number of new cases of a disease, c) Prevalence is the total number of cases both new and existing at a point in time, and d) Morbidity is the state of being diseased or the number of diseased individuals.
The correct answer is b) Incidence.