Answering Questions about Population Characteristics

Abstract

It is often the purpose of a statistical investigation to answer a yes-or-no question about some characteristic of a population. An election candidate, for example, may employ a pollster to determine whether the proportion of voters intending to vote for him does or does not exceed 1/2. The polio vaccine trial was designed so that medical researchers could decide whether the incidence rate of polio is or is not smaller in a population of persons inoculated with the vaccine than in a population of persons not inoculated with the vaccine. Industrial quality control involves determination as to whether the average strength, lifetime, or concentration of the product in each manufacturing batch does or does not fall within acceptable limits.