Notes prepared by pamela peterson drake 1 correlation and regression basic terms and concepts 1. Setting up multicollinearity test multiple regression. Almost all testing is automated no time for quality assurance. Childrens iq scores at age 4 and age 5 should be positively. Automating also reduces the time taken for regression testing. Reset all this is one of the methods for regressiontesting in which all the tests in the existing test. No changes must be allowed to code, during theregression test phase. Pdf software regression testing rt verifies previous features on a software. The flow chart shows you the types of questions you should ask yourselves to determine what type of analysis you should perform. The importance of regression testing with selective. Introduction to binary logistic regression 6 one dichotomous predictor. Inference t test inferencefromregression in linear regression, the sampling distribution of the coe. Picturing the world, 3e 3 correlation a correlation is a relationship between two variables. Regression technique used for the modeling and analysis of numerical data exploits the relationship between two or more variables so that we can gain information about one of them through knowing values of the other regression can be used for prediction, estimation, hypothesis testing, and modeling causal relationships.
Reduces the need for manual testing and discovers defects manual testing cannot expose and. Proper understanding of the need for regression testing and due diligence in the identification of regression test cases would go a long way in determining the success of the project. The adobe flash plugin is needed to view this content. I the simplest case to examine is one in which a variable y, referred to as the dependent or target variable, may be. It can reduce the cost of applying tests by storing the expected result. There is a saying, pay less for testing during software development or pay more for maintenance or correction later. Regression testing is a normal part of the program development process and, in larger companies, is done by code testing specialists. Regression when all explanatory variables are categorical is analysis of variance. The test strategy document is maintained throughout the life of a project. The test strategy document describes the scope, approach, resources and schedule for the testing activities of the project. A scatter plot is a graphical representation of the relation between two or more variables.
For the data at hand, the regression equation is cyberloafing 57. The regression is spurious when we regress one random walk onto another independent random walk. The paper will be approximately 10 pages, and that will include datadata analysis. Run and interpreting hierarchical regression in spss 4. Sir francis galton inheritance data galtons graph powerpoint presentation regression fallacy horace secrist from wikipedia powerpoint presentation cover jinx. Good regression tests give us confidence that we can change the object of test while maintaining its intended behaviour. In it world a regression means the return of a bug. Use the two plots to intuitively explain how the two models, y. One year later the same children are given another iq test. Often you can find your answer by doing a t test or an anova. Jun 03, 20 what is this term regression regression means errors that occurs due to someaction or activities in a system.
Ppt regression testing powerpoint presentation free to. Differentiate between hierarchical and stepwise regression 3. All test can be executed automatically at any time. This page contains software testing seminar and ppt with pdf report. In correlation, the two variables are treated as equals. Tests are selected based on the area of frequent defects. If using categorical variables in your regression, you need to add n1 dummy variables. Times gillsans helvetica blank presentation regression to mediocrity midterm scores why. Nov 10, 2019 how to deliver a winning qa testing presentation to the team the demonstrations, meetings and presentations are critical skills for a software tester to share knowledge and stay current. Presentation of regression results ive put together some information on the industry standards on how to report regression results. Cognitive function is measured by the digit symbol substitution test dsst. The residuals statistics show that there no cases with a standardized residual beyond three standard deviations from zero. Multiple linear regression and matrix formulation introduction i regression analysis is a statistical technique used to describe relationships among variables.
One reason is the dynamic nature of software product. For each program modification all tests must be passed before the modification is regarded as complete regression testing test first implement later. Regression testing is the process of testing changes to computer programs to make sure that the older programming still works with the new changes. Ppt regression powerpoint presentation free to download. Regression will be the focus of this workshop, because it is very commonly. Linear regression is an algorithm that every machine learning enthusiast must know and it is also the right place to start for people who want to learn machine learning as well. Prioritizing test cases for regression testing powerpoint ppt presentation. Testing regression testing is not a simple extension of testing main differences are. The role of the two significant observations if you see one, check if it is a mistake. The data can be represented by the ordered pairs x, y where x is the independent or explanatory variable, and y is the dependent or response variable.
In this article, we share our 30years software testing experience and show an example of how regression testing was run in our project featuring an image processing application. In simple terms, regression analysis is a quantitative method used to test the nature of relationships between a dependent variable and one or more independent variables. The fact that regression test is the one last chance for us to catch the bug before the application go live, makes regression testing even more important. Lysosomal storage disorder testing if coarse facial appearance. Test department coders develop code test scenarios and. Linear regression once weve acquired data with multiple variables, one very important question is how the variables are related. Pros and cons to ensure effective regression tests, observe thefollowing. Presentation of regression results regression tables. Verma msc statistics, phd, mapsychology, masterscomputer application professorstatistics lakshmibai national institute of physical education, gwalior, india deemed university email. The purpose of the regression suite is to make sure that the software behavior is unchanged unless due to data change or latest software. In this tutorial, we will learn to create regression test cases. The database used for regression testing must beisolated.
Spend your time thinking about creative solutions rather than interpreting the code. Regression testing provides a tool for managing change. Childrens iq scores at age 4 and age 5 should be positively correlated. Here are my tips on making an effective qa testing presentation. The multiple regression process conceptually, multiple regression is a straight forward extension of the simple linear regression procedures. Regression testing is any type of software testing that seeks to uncover new errors, or regressions, in existing functionality after changes ha. Well just use the term regression analysis for all these variations.
Scope of test testing aims to check the correctness of the whole program regression testing aims to check modified parts of the program 3. Regression analysis allows us to estimate the relationship of a response variable to a set of predictor variables. How to prepare and deliver an outstanding qa testing. Time pressure is well known and increasing because too many defects are found late and have to be repaired. Ha null hypothesis is the denial of the research hypothesis. Sex discrimination in wages in 1970s, harris trust and savings bank was sued for discrimination on the basis of sex. In this paper, we describe several techniques for prioritizing test cases for regression testing. Under this technique is a hybrid approach of both regression test selection and test case prioritization. It is spurious because the regression will most likely indicate a nonexisting relationship. Chapter 9 linear regression and correlation content 1. Code being regression tested should be under aconfiguration management tool. Availability of test plan testing starts with a specification, an implementation of the specification and a test plan blackbox andor whitebox test cases. Multiple regression multiple regression typically, we want to use more than a single predictor independent variable to make predictions regression with more than one predictor is called multiple regression motivating example.
Regression testing rarely non regression testing is rerunning functional and nonfunctional tests to ensure that previously developed and tested software still performs after a change. Presentations ppt, key, pdf logging in or signing up. Regression testing means the testing process that isdone to find the regressions in the system after doingany changes in the product. Suppose a group of children is given an iq test at age 4. The regression coefficient r2 shows how well the values fit the data. System, acceptance, and regression testing learning objectives. Its not perfect, but it is a rough model of the oral presentation skills that i expect for your presentation. Linear regression and correlation powerpoint ppt presentation. Powerpoint presentation at the rpcisoa conference, tahoe city, ca. The presentations should last approximately 15 minutes, and include visual aids. Changes that may require regression testing include bug fixes, software enhancements, configuration changes, and even substitution of electronic components. Suppose the probability density function of the random variable t is given by f t.
This is one of the methods for regression testing in which all the tests in the. The observations are independent regression picture recall example. Further complexity is added as the products functionalities and capabilities expand. As treated 3day gaps switching study drug, therapy gap, admission to nursing facilityhome or transfer to hospice care, start of dialysis or receipt of a kidney transplant, disenrollment from medicare, study end. Mediation is a hypothesized causal chain in which one variable affects a second variable that, in turn, affects a third variable. Regression testing is nothing but a full or partial selection of already executed test cases which are reexecuted to ensure existing functionalities work fine. Requires knowledge about the system and how it affects by the existing functionalities.
For example, we could ask for the relationship between peoples weights and heights, or study time and test scores, or two animal populations. Regression test each month prior to system jar release cloud testing prior to maintenance updates regression test prior to each deltek cloud update monthly maintenance releases regression test each month against costpoint 8. Here n is the number of categories in the variable. Chapter 305 multiple regression introduction multiple regression analysis refers to a set of techniques for studying the straightline relationships among two or more variables. Mejbah alam, justin gottschlich, nesime tatbul, javier turek. In the example below, variable industry has twelve categories type. Regression test code must bekept immune to developer changes.
The regression coefficients can thus be interpreted as the relative risk when the value of the. Regression analysis is a quantitative research method which is used when the study involves modelling and analysing several variables, where the relationship includes a dependent variable and one or more independent variables. A free powerpoint ppt presentation displayed as a flash slide show on id. Regression testing is defined as a type of software testing to confirm that a recent program or code change has not adversely affected existing features. This includes defining what will be tested, who will perform testing, how testing will be managed, and the associated risks and contingencies. Linear regression using stata princeton university. Chisquare compared to logistic regression in this demonstration, we will use logistic regression to model the probability that an individual consumed at least one alcoholic beverage in the past year, using sex as the only predictor. Regression with categorical variables and one numerical x is often called analysis of covariance. An introduction to logistic regression johnwhitehead department of economics appalachian state university outline introduction and description some potential problems and solutions writing up the results introduction and description why use logistic regression. Pearsonproduct moment correlation coefficient r a measure of the relation between x and y, but is not standardized to standardize, we divide the covariance. Show that in a simple linear regression model the point lies exactly on the least squares regression line. See the selective adoption recommended practices for more information.
It is a tool in helping to provide stability in the face of code change. Pearson product moment correlation ppt xpowerpoint. Testing is the last step in the software life cycle. Regression testing can be used throughout the lifecycle. The set of the automated test suite can form a regression test suite. Sep 04, 2016 presentation on regression analysis 1. Ppt regression testing powerpoint presentation free to view id. Everything is new regression testing starts with a possibly modified. This is one of the methods for regression testing in which all the tests in the existing test bucket or suite should be reexecuted. Scribd is the worlds largest social reading and publishing site. Ppt prioritizing test cases for regression testing powerpoint. It mediates the relationship between a predictor, x, and an outcome.
Regression testing how to make regression testing more. Chapter 565 cox regression introduction this procedure performs cox proportional hazards regression analysis, which models the relationship between a. These terms are used more in the medical sciences than social science. Regression testing examples include iteration regression and full regression, and both can be covered with manual and automated test cases. Originally based on extreme programming principles. Lecture estimation and hypothesis testing for logistic. Regression regression analysis is used to predict the value of one variable the dependent variable on the basis of other variables the independent variables. To view this presentation, youll need to allow flash. Pdf regression testing of database applications under an. Software testing 4 given below are some of the most common myths about software testing. Automated unit test suite helps find the problems at an earlier stage. Regression thus shows us how variation in one variable cooccurs with variation in another. Pearsonproduct moment correlation coefficient r ppt. Simple linear regression is a bivariate situation, that is, it involves two dimensions, one for the dependent variable y and one for the independent variable x.
Regression testing starts with a possibly modified specification, a modified program, and an old test plan which requires updating 2. Every paper uses a slightly different strategy, depending on authors focus. A normal regression testing is performed to verify if the build has not broken any other parts of the application by the recent code changes for defect fixing or for enhancement. Simple linear regression an analysis appropriate for a quantitative outcome and a single quantitative explanatory variable. In the scatter plot of two variables x and y, each point on the plot is an xy pair. Analysis of variance for days source df ss ms f p treatmen 2 34. Regression testing is easy to define and understand, but baffling when it comes to perform regression testing of a software product. The residuals statistics show that there no cases with a standardized residual beyond three.