1.1 Introducing Statistics: What Can We Learn from Data?

Identify components within a statistical study.

• A statistical study is a study in which data are collected from a sample to answer an investigative question about a larger population.
• Statistical studies are necessary when the population is too large or it is too difficult to collect data from every item or individual in the population.
• A datum (singular form of data) is a piece of information about an item or individual. A collection of data is called a data set.
• A population consists of all items or individuals of interest. The population size is represented by the symbol N.
• A sample selected for study is a subset of the population from which data are obtained. The number of items in the sample, called the sample size, is represented by the symbol n.
• Each component of a statistical study and the resulting calculations can be related to an aspect of the corresponding real-world context from which the components were derived. This identification of a statistical result with the corresponding contextual component is what is meant by “in context.”

Determine an investigative question within a statistical study.

• An investigative question for a specific study should have a defined purpose and should not be changed based on the data analysis or results.
• An investigative question should be posed so that the required data can be collected and analyzed. 31 Exploring One-Variable Data and Collecting Data TOPIC 1.2 Variables UNIT 1