From 1912 to 1928, the contact number for measles in the U. S. was 12.8. If we assume that Ro is still 12.8 and that inoculation is 100% effective -- everyone inoculated obtains immunity from the disease -- what fraction of the population must be inoculated to prevent an epidemic?

How can changes in technology or consumer demand make it difficult for people to get jobs? by changing the number or kind of jobs available by making it possible for some people to work fewer hours by making it difficult for people to buy what they want by creating a demand for things that are not available

Persons who have not yet attained the legal age of consent under the applicable laws in the jurisdiction in which the research was approved. persons who are under 18 years of age. persons who have not yet attained the legal age of consent under the applicable laws in the jurisdiction in which the research will be conducted. persons who are under 21 years of age.

On average, being married has a(n) effect on happiness.