Statistics How To

Hypothesis Testing > One Sample Z Test Before reading this, you may find it helpful to review: What is a Normal distribution? What is a Z-score? How to Run a One Sample Z Test A one sample z test is one of the most basic types of hypothesis test. In order to run a one … Read more

Goodness of Fit > Anderson-Darling Goodness of Fit What is the Anderson-Darling Test? The Anderson-Darling Goodness of Fit Test (AD-Test) is a measure of how well your data fits a specified distribution. It’s commonly used as a test for normality. Performing the AD-Test by Hand The hypotheses for the AD-test are: H0: The data comes … Read more

Statistics Blog > sigma / sqrt (n) You’ll come across a couple of different formulas when calculating z-scores: When I first started learning statistics, the different formulas completely confused me. They still do (a little) and I have to think about what I’m doing every time I calculate a z-score. In order to figure out … Read more

Statistics Definitions > Clustering / Cluster Analysis What is Clustering? Clustering in statistics refers to how data is gathered (“clustered”) by factors like: Age. Household size. Income. Or education level. Sorting data into clusters sometimes leads to more investigation into the data. For example, cancer clusters can indicate some problem in the environment. Or, they … Read more

Probability and Statistics > TI-83 for Statistics > how to find t critical value on ti 83 IMPORTANT: The TI-83 doesn’t have a function to calculate the t critical value directly. In other words, you won’t find it listed on a menu as something like “invT”. However, you can calculate it; it just takes a … Read more

Hypothesis Testing > Standardized Values Standardized values (also called standard scores or normal deviates) are the same thing as z-scores. A standardized value is what you get when you take a data point and scale it by population data. It tells us how far from the mean we are in terms of standard deviations. This … Read more

Statistics Definitions > Density Curve Examples What is a Density Curve? A density curve is a graph that shows probability. The area under the curve is equal to 100 percent of all probabilities. As we usually use decimals in probabilities you can also say that the area is equal to 1 (because 100% as a … Read more

Statistics Definitions > Continuous variables can take on an infinite number of variables. For example, you could have a random variable Y that represents possible weights: The probability distribution function shown above shows all possible values for Y, which for this case, has an infinite amount of possibilities. For example, the random variable Y could … Read more

Probability > Contents: What is Predictive Analytics? Marketing Analytics Healthcare Analytics Real Life Examples Analytical Tools Software for Predictive Analytics Tips for Making Good Predictions What is Predictive Analytics? Predictive analytics is a way to predict future events based on past behavior. It’s a combination of statistics and data mining; Tools from both areas are … Read more

Probability and Statistics > TI 83 for Statistics > TI 83 List One of the first things you’ll need to do in statistics is to create a TI 83 list for data. Many functions on the TI 83 can be done without lists (by entering a string of numbers on the home screen), but creating … Read more