1. Introduction What are the meanings of different types of ANOVA? In other words, what are Type 1 (Type I), Type 2 (Type II), and Type 3 (Type III) ANOVA? The following uses the model of factors A and B, and its interaction A*B as an example to explain the difference of Type 1 (Type … Read more
Two sample t-test is also called independent sample t-test or unpaired sample t-test. This tutorial explains what two sample t-test is, its formula, and examples of two sample t-test. Definition and Example Two sample t-test is used to test whether means from two different groups of people or objects are significantly different. The name of … Read more
One-Way ANOVA is to compare the means of different groups, to see whether the mean difference is statistically significant. For instance, you would like to compare the average household size of three cities. You can collect 3 samples from these three cities and conduct a one-way ANOVA to check the difference. Formulas of One-way ANOVA … Read more
What is Correlation? Correlation is a statistical measure of the relationship between two variables, X and Y. For instance, you can measure to what extent temperature (X) is related to the production of ice cream (Y). You probably would expect that higher temperatures correspond with higher production of ice cream. On the plot shown below, … Read more
How to Write Null and Alternative Hypotheses
Since both correlation and t-test are about relationships between X and Y, what is the difference between them and when do you use t-test (or correlation)? This tutorial aims to answer these two questions. The following figure presents the difference between t-test and correlation. In particular, t-test deals with situations where X is a binary … Read more
This tutorial explains what t-test is, and the difference between independent sample t-test and paired sample t-test. It also explains what two-sample and one-sample t-test are. What is independent sample t-test? Indepdent sample t-test examines whether the means from 2 separate groups of people or objects are statistically significantly different. That is, we calculate two … Read more
This short tutorial shows how you can calculate standard deviation in Python using NumPy.