 # Stats

Cohen's kappa in SPSS - Procedure, output and interpretation of the output using a relevant example. Introduction In research designs where you have two or more raters (also known as "judges" or "observers") who are responsible for measuring a variable on a categorical scale, it is important to determine whether such raters agree. Cohen's kappa (κ) is such a measure of inter-rater agreement for categorical scales when there are two raters (where κ is the lower-case Greek letter 'kappa'). There are many occasions when you need to determine the agreement between two raters. For example, the head of a local medical practice might want to determine whether two experienced doctors at the practice agree on when to send a patient to get a mole checked by a specialist. Both doctors look at the moles of 30 patients and decide whether to "refer" or "not refer" the patient to a specialist (i.e., where "refer" and "not refer" are two categories of a nominal variable, "referral decision").

Difference between ANOVA and MANOVA? Thanks Vagelas, Explanation and provided links are very useful and helpful Dear Abdul, “ANOVA” stands for “Analysis of Variance” while “MANOVA” stands for “Multivariate Analysis of Variance.”The ANOVA method includes only one dependent variable while the MANOVA method includes multiple, dependent variables.ANOVA uses three different models for experimentations; random-effect, fixed-effect, and multiple-effect methods to determine the differences in means which is its main objective while MANOVA determines if the dependent variables get significantly affected by changes in the independent variables. Further reading. Exact Unconditional Tests. FAQ 1790 - Choosing a statistical test. This is chapter 37 of the first edition of Intuitive Biostatistics by Harvey Motulsky. Copyright © 1995 by Oxford University Press Inc. Chapter 45 of the second edition of Intuitive Biostatistics is an expanded version of this material. This book has discussed many different statistical tests. Free Effect Size (Cohen's d) Calculator for a Student t-Test. How do I analyze data in SPSS for Z-scores? Background | Enter Data | Analyze Data | Interpret Data | Report Data Analyze Click “Analyze,” “Descriptive Statistics,” and then “Descriptives.” Descriptives box This box will appear. How do I interpret data in SPSS for Pearson's r and scatterplots? Correlations Box Take a look at the first box in your output file called Correlations. You will see your variable names in two rows. In this example, you can see the variable name ‘water’ in the first row and the variable name ‘skin’ in the second row. You will also see your two variable names in two columns. How to Analysis Data with Low Quality or Small Samples, Nonparametric Statistics. General Purpose Brief review of the idea of significance testing. To understand the idea of nonparametric statistics (the term nonparametric was first used by Wolfowitz, 1942) first requires a basic understanding of parametric statistics. Elementary Concepts introduces the concept of statistical significance testing based on the sampling distribution of a particular statistic (you may want to review that topic before reading on). How to Use SPSS: Intra Class Correlation Coefficient. IBM Knowledge Center. Introduction to ANOVA / MANOVA. A general introduction to ANOVA and a discussion of the general topics in the analysis of variance techniques, including repeated measures designs, ANCOVA, MANOVA, unbalanced and incomplete designs, contrast effects, post-hoc comparisons, assumptions, etc. For related information, see also Variance Components (topics related to estimation of variance components in mixed model designs), Experimental Design/DOE (topics related to specialized applications of ANOVA in industrial settings), and Repeatability and Reproducibility Analysis (topics related to specialized designs for evaluating the reliability and precision of measurement systems). See also, General Linear Models and General Regression Models; to analyze nonlinear models, see Generalized Linear Models. Basic Ideas The Purpose of Analysis of Variance In general, the purpose of analysis of variance (ANOVA) is to test for significant differences between means.

Multiple Regression. General Purpose The general purpose of multiple regression (the term was first used by Pearson, 1908) is to learn more about the relationship between several independent or predictor variables and a dependent or criterion variable. For example, a real estate agent might record for each listing the size of the house (in square feet), the number of bedrooms, the average income in the respective neighborhood according to census data, and a subjective rating of appeal of the house. Parametric versus non-parametric. Repeated-measures ANOVA. Also known as within-subjects design, theses tests are used when each subject is measured multiple times. Different treatments may applied to each subject over time, or to groups of subjects in a uniform way. Similar to paired t-tests, these tests increase the power of the analysis by accounting for the idiosyncratic differences between subjects. The following conditions make a study appropriate for repeated-measures ANOVA: Research Methods - Measurement scales. A topic which can create a great deal of confusion in social and educational research is that of types of scales used in measuring behaviour. It is critical because it relates to the types of statistics you can use to analyse your data. An easy way to have a paper rejected is to have used either an incorrect scale/statistic combination or to have used a low powered statistic on a high powered set of data. Nominal The lowest measurement level you can use, from a statistical point of view, is a nominal scale. Statistical Tests in SPSS. What statistical analysis should I use? Statistical analyses using SPSS Introduction This page shows how to perform a number of statistical tests using SPSS. Each section gives a brief description of the aim of the statistical test, when it is used, an example showing the SPSS commands and SPSS (often abbreviated) output with a brief interpretation of the output.

Types of Statistical Tests. Now that you have looked at the distribution of your data and perhaps conducted some descriptive statistics to find out the mean, median or mode, it is time to make some inferences about the data. As previously covered in the module, inferential statistics are the set of statistical tests we use to make inferences about data. These statistical tests allow us to make inferences because they can tell us if the pattern we are observing is real or just due to chance.