سؤال قراءة ستيب محلول — فهم التفاصيل (تدريب 6115)

(1) In statistics, we generally want to study a population. You can think of a population as a collection of persons, things, or objects under study. To study the population, we select a sample. The idea of sampling is to select a portion of the larger population and study that portion (the sample) to gain information about the population. (2) Data are the result of sampling from a population. Because it takes a lot of time and money to examine an entire population, sampling is a very practical technique. IfIfyou wished to calculate the overall grade point average at your school, it would make sense to select a sample of students who attend the school. The data collected from the sample would be the students’ grade point averages. In presidential elections, opinion poll samples of 1,000 to 2,000 people are taken. The opinion poll is supposed to represent the views of the people in the entire country. Manufacturers of canned carbonated drinks take samples to determine if a 16-ounce can contain 16 ounces of carbonated drink. From the sample data, we can calculate a statistic. A statistic is a number that represents a property of the sample. (3) One of the main concerns in the field of statistics is how accurately a statistic estimates a parameter. The accuracy really depends on how well the sample represents the population. The sample must contain the characteristics of the population in order to be a representative sample. How can statistics be more accurate?