STAT 22500 Lecture Notes - Lecture 2: Statistical Inference, Convenience Sampling, Descriptive Statistics

• School: Purdue University
• Department: Statistics
• Course: STAT 22500
• Professor: Tim Reese

Document Summary

This occurs when the sample is selected in such a way that favors the selection of elements with a particular characteristic. If a statistic is biased it will tend to overestimate or underestimate the value, we are trying to predict. We can eliminate or minimize bias by using proper sampling techniques. Convince sampling-uses results or data that are conveniently and readily obtained. Data from this type of sample runs the risk of being severely biased and should not be generalized to the overall population (cannot use to conduct inferential statistics) Descriptive statistics can be calculated for the data, however, these numbers can only be used to describe the sample. Voluntary response sample-common convenience sample letting subjects volunteer. This kind of sample typically over-represents people with strong opinions. A sample to be useful when conducting inferential statistics, it needs to be representative of the population. This is one way to get a representative sample.