Survey

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Survey

Document related concepts

Transcript

LIS 397.1 Introduction to Research in Library and Information Science Choosing an Appropriate Statistical Test Procedure R. E. Wyllys Copyright 2003 by R. E. Wyllys Last revised 2003 Jan 15 School of Information - The University of Texas at Austin LIS 397.1, Introduction to Research in Library and Information Science How to Choose a Standardized Statistical Test • Choice depends on your real-life problem • Figure out how many variables are involved – If just one variable, decide how many populations (groups) are involved – If two variables, consider nature of variables: interval or categorical School of Information - The University of Texas at Austin LIS 397.1, Introduction to Research in Library and Information Science How to Choose a Standardized Statistical Test • 1-Variable Problems: Is your question: – Does the variable have a particular mean value in some population? Use • Confidence interval – Does the variable average the same (i.e., does it have the same mean) in two populations? Use either • t-Test for dependent samples (if pairs of observations can be made on each element of your sample); else, t-Test for independent samples; or • ANOVA with repeated values (if paired observations can be made); else, ANOVA without repeated values School of Information - The University of Texas at Austin LIS 397.1, Introduction to Research in Library and Information Science How to Choose a Standardized Statistical Test • 2-Variable Problems: Is your question: – Is there some correlation or association between the variables? Use • Pearson correlation if variables are interval type • Chi-square test of association if variables are categorical type – Is it possible to estimate (predict) the value of one of a pair of interval variables on the basis of observing the value of the other? Use • Linear regression School of Information - The University of Texas at Austin LIS 397.1, Introduction to Research in Library and Information Science After You Choose a Standardized Statistical Test • Choose the level of significance (or the confidence level) at which you want to work • Make your observations and enter them into an appropriate computer program • Using the program, apply your chosen test to your data • Note the resulting values of your test statistic and the probability or significance that the program reports for the test statistic • Accept or reject the null hypothesis that is built into the procedure you have used. • Interpret your decision with respect to your real-world problem School of Information - The University of Texas at Austin LIS 397.1, Introduction to Research in Library and Information Science Statistics and Statistical Tests Can Be Valuable Tools in Solving Problems School of Information - The University of Texas at Austin LIS 397.1, Introduction to Research in Library and Information Science