Type of Statistics

When we talk about statistics, there are two different subdivisions: descriptive and inferential. A descriptive statistic is a statistic that describes just the data collected. Perhaps you are interested in the average GPA of a Fort Lewis student. You survey your Math 132 class and find that the average GPA of the class is 3.21. The average GPA of 3.21 is a descriptive statistic if it is only used to describe that particular Math 132 class. Now if the average GPA of 3.21 was then stated as the average GPA of ALL Fort Lewis students, then it becomes an inferential statistic. Inferential statistics are statistics that have been generalized beyond just the data collected. The average of 3.21 was collected from only a few FLC students, but then generalized to all students.

Descriptive & Inferential Statistics

Week 1 Reading Check: Descriptive & Inferential Statistics

Types of Research

When doing statistical research, there are several types that can be conducted. A descriptive study is a study that focuses on a single variable, and does not generalize the results beyond the data that was actually collected/studied. This type of study merely describes situations. Another type of research is the correlational study. In a correlational study, you are looking for a relationship between variables. Two variables are studied in a correlational study (they can be quantitative, qualitative, or one of each). Cause and effect can NOT be determined from correlational research. The independent variable of correlational research may be qualitative, two groups, that were pre-existing or otherwise NOT randomly assigned. If you do wish to explore cause and effect relationships, you will have to conduct an experiment. The independent variable MUST contain at least two qualitative groups where subjects have to have been randomly assigned. A study is not considered to be an actual 'experiment' if the independent variable groups were not randomly assigned. Later in this course, we will conduct both correlational research and experiments via statistical hypothesis testing.

Khan Academy on Types of Statistical Studies [9:51]

Week 1 Reading Check: Types of Research

Student Course Learning Objectives

Define basic statistics vocabulary (e.g., levels of measurement (nominal, ordinal, interval, ratio), discrete vs. continuous variables, descriptive vs. inferential statistics, sample vs. population, independent vs. dependent variable, explanatory vs. response variable, confounding variables, experimental vs. observational)

Attributions

Adapted from "Introductory Statistics" by OpenStax is licensed under CC BY 4.0.