Final answer:
The statistical device that identifies a portion of 100 is called the percentage. It is calculated by dividing the part by the total and multiplying by 100 and is essential in both describing data and making inferences about a population based on a sample.
Step-by-step explanation:
The statistical device that identifies a portion of 100 is called the percentage. Percentage calculations are used to express a part as a fraction of 100. The formula to calculate a percentage is part divided by the total, then multiplied by 100, which can be represented as (part/total) × 100.
In the context of inferential statistics, such calculations are crucial. For example, if a certain number of samples are found to be defective, a percentage can indicate what portion of the whole population might similarly be defective. Importantly, when a figure like "95 percent confidence" is mentioned, it refers to the level of certainty that the true statistical measure (like a mean or a proportion) for a population is within a specified interval.
For instance, if a survey found that 50 percent of high school seniors plan to attend a four-year college, this figure represents a parameter (if the survey includes the entire population) or a statistic (if the survey includes only a sample) depending on the context. These concepts help us understand and describe data more effectively.