Useful tips for everyday
Is sample covariance matrix positive definite? Covariance and correlation matrices, and sample covariance and sample correlation matrices, are always positive semi-definite. Can a covariance matrix…
How to understand Bayesian prior and posterior distributions? Gather data. Update your prior distribution with the data using Bayes’ theorem to obtain a posterior distribution.…
What is the interaction between the two factors? The interaction is the simultaneous changes in the levels of both factors. If the changes in the…
Does AUC change with threshold? Note: AUC is not dependent on classification threshold value. Changing the threshold value does not change AUC because it is…
What is power in correlation? The power of a test is calculated as 1-beta and represents the probability that we reject the null hypothesis when…
Does correlation change with outliers? In most practical circumstances an outlier decreases the value of a correlation coefficient and weakens the regression relationship, but it’s…
How can DNA purity be improved? These include the following: Salting out using an appropriate cosmotrope such as potassium acetate. Extraction using organic solvents and…
How are people selected for a probability sample? In probability sampling, respondents are randomly selected to take part in a survey or other mode of…
Which is an example of a likelihood ratio test? Example of a likelihood ratio test. As discussed above, the LR test involves estimating two models…
What is the x value in probability? P(X = x) refers to the probability that the random variable X is equal to a particular value,…