Introduction The more advanced methods in statistics have generally been developed to answer real-world questions, and ANOVA is no different. How do we answer questions in the real world, as to which route from home to work on your daily commute is easier, or How would you know which air-conditioner to choose out of a […]Read more "Two Way ANOVA in R"
A quick experiment in R can unveil the impact of sample size on the estimates we make from data. A small number of samples provides us less information about the process or system from which we’re collecting data, while a large number can help ground our findings in near certainty. See the earlier post on […]Read more "Animated: Mean and Sample Size"
Outliers are points in a data set that lie far away from the estimated value of the centre of the data set. This estimated centre could be either the mean, or median, depending on what kind of point or interval estimate you’re using. Outliers tend to represent something different from “the usual” that you might […]Read more "Simple Outlier Detection in R"
Linear systems are systems that have predictable outputs when there are small changes in the inputs to the system. Nonlinear systems are those that produce disproportionate results for proportional changes in the inputs. Both linear and non-linear systems are common enough in nature and industrial processes, or more accurately, many industrial and natural processes can […]Read more "Animated Logistic Maps of Chaotic Systems in R"
Background For a lot of people, the rubber hits the road in data analysis when they can describe the relationships between everyday things they deal with. How does the gas mileage of the cars we manufacture vary with the vehicle’s weight, or the size of the wheels? How does the fuel that consumers use change the […]Read more "Linear and Polynomial Models in R"
Not all data in this world is predictable in the exact same way, of course, and not all data can be modeled using the Gaussian distribution. There are times, when we have to make comparisons about data using one of many distributions that represent data which could show different patterns other than the familiar and […]Read more "Comparing Non-Normal Data Graphically and with Non-Parametric Tests"
In my earlier posts on hypothesis testing and confidence intervals, I covered how there are two hypotheses – the default or null hypothesis, and the alternative hypothesis (which is like a logical opposite of the null hypothesis). Hypothesis testing is fundamentally a decision making activity, where you reject or fail to reject the default hypothesis. […]Read more "Power, Difference and Sample Sizes"