Dealing with statistics. On Wednesday, we’ll be meeting in the computer lab in room 109.
Statistics is the science of collecting, arranging, analyzing, and interpreting information. Data is collected in the form of measurements or counts. A measurable characteristic is called a variable. If a variable could assume any real value between certain limits, it is a continuous variable. If the variable can only assume a finite set of values or as many values as their are whole numbers, it is referred to as a discrete variable.
The process of statistics has four basic steps.
- Identify the research objective. The objective must be detailed enough to identify a specific group to be studied.
- Collect the information needed to answer the questions posed in Step 1. Gather a statistically valid subset of the study group and collect data from/on that subset.
- Organize and summarize the information. This step is referred to as descriptive statistics. Tescriptive statistics describes the information collected through numerical measurements, graphs, charts, tables, and so forth.
- Draw conclusions from the information. Generalize the information collected to the population as a whole.
Inferential Statistics uses methods that generalize results obtained from a sample to the population and measure their reliability.
Random sampling is preferred for choosing the specific members of the group being studied who will be members of the subset which data is collected from/on.
The collected are called raw data. To represent the collected data, tables or graphs are commonly used. The two most popular methods for graphical display of data are pie charts, for data represented as portions of a whole, and bar graphs, for displaying relative magnitudes. Both forms of display are only useful when the data can be divided into discrete categories.