Vectoronica

In this page, i'm going to talk about spearman correlation and the runs test1. spearman correlation : A correlation coefficient, is a standardized measure to express the degree by which two variables are associated. The standardization implies that it has a fixed range over which it varies. Most correlation coefficients vary between -1 and +1. In general, the Pearson correlation coefficient is ..

In this blog, i'm going to talk about Mann-Whitney test and Kruskal-Wallis test 1. Wilcoxon/Mann-Whitney test : To evaluate whether two samples could originate from the same distribution, a T-test is often used to evaluate whether just the means of the two samples are different. To test the same basic hypotheses, you could also look at other statistics, the mean rank. The test using this statist..

In this blog, what I want to talk about is the sign test and Wilcoxon signed rank test. 1. The sign test : It translates the direction of the difference between two observations, not necessarily a numerical difference, into a variable with two categories and subsequently applied a one-sample test for a proportion. It's called the sign-test. This test offers a nonparametric alternative to a one s..

In this page, i'm going to talk about assumptions and tests in terms of factorial ANOVA and the link between ANOVA and multiple regression. 1. Assumptions : the assumptions are the same as in one way ANOVA. 1-1) assumptions The observation should be independent The response variables should be normally distributed in each group The variances need to be homegeneous or the same. With unequal sampl..

What I'm going to do in this blog is talking about one way ANOVA-post hoc t-tests and factorial ANOVA. 1. One way ANOVA-post hoc t-tests : it just means how to follow up a significant F-test in one way ANOVA with pairwise comparisons of group means using pairwise t-tests or confidence intervals. They tell us which group means differ significantly and in what direction. 1-1) Follow up comparisons..

What I want to share in this blog is a basis of null space and column space. 1. a null space and a column space: I told you these in an earlier blog, but I'm going to talk about these again for a quick review. the null space is a set that contains vectors that make an equation a matrix A times a vector x 0. Here it is. column space is a lot easier to understand, which is a set of column vectors ..

What i want to talk about in this page is One way ANOVA and assumptions and F-test for one way ANOVA. 1. One way ANOVA : Analysis of variance(known as ANOVA) allows us to compare means of more than two groups. It's a method of analysis we use in research designs with a quantitative response variable and one or more independent variables. One way ANOVA uses one response variable and independent v..

In this blog, i'm going to talk about categorical response variable. 1. Categorical response variable : Until now, I looked at regression models that describe or predict a quantitative variable, but there are also regression models for ordinal and nominal response variable. 1-1) logistic function : The logistic function has a sigmoid shape or s curve. This produces estimated values that lie betw..