Getting Started Using R
Getting started working with R programming language
When R software and RStudio program have been installed on your computer, R working session can be simply started by clicking the RStudio app from your Windows start menu.
R Data Structure Dataset
Creating and indexing a list in R
list is a type of data structure in R programming language. Unlike other data structures, especially matrix and vector, in which each element must has the same type of data, a list provides the flexibility of storing various information in one object.
ggplot2
Violin plots with ggplot2 in R
Violin plot is quite similar as boxplot, in the sense that it shows the range of the data. And at the same time a violin plot illustrates the data distribution shape with a density curve on both sides of the central pillar.
Python
Passing a List to Function in Python
When we perform data analysis using Python, it is often useful to pass a list in calling the function as we want each element of the list to be accessed by the function.
R Programming
Using t-distribution and t-test with R
A Student t-distributed random variable is modeling the ratio between a standard Normal random variate and square root of a Chi-squared random variable divided by its degrees of freedom.
ggplot2
Kernel density plots with ggplot2 in R
Kernel density function is a nonparametric method to find the drawing density curve of random samples, and it is often used to draw a smoothed curve in data visualization. In R programming with ggplot2 package, a chaining of functions ggplot() and geom_density() is often used to draw different smoothed curves showing the distribution of continuous variables.
Python
Using a function with a while loop in Python
A function in Python is a group of code statements wrapped together to perform specific tasks. After a function is defined, then it can be called by passing real values to its arguments and get the returning results. A while loop in Python is a group of conditional statements bundled in a statement beginning with keyword ‘while’, and the codes will run forever until the condition returns false. By including a user-defined function inside a while loop in Python, many iterative tasks can be fulfilled.
Python
Poisson distribution implementation in Python
Poisson distribution is a discrete distribution. It is frequently used to model the counts of event occurrence during a specified time interval, such as telephone calls coming in to a call center in a given day. There is one parameter in the Poisson probability function, λ, which denotes the constant occurring rate in a Poisson process.
Python
Calculating Type I Error and Type II Error in Hypothesis Testing using Python
In hypothesis testing, the possibility of the other side than the conclusion usually exists, and the analysis commits so-called Type I and Type II errors, with respect to the truth and the decision made upon the random sample and hypotheses. In particular, a Type I error measures the probability that a true Null hypothesis (H0) is incorrectly rejected, and a Type II error says the probability that a false H0 not being rejected, respectively.
R Programming
Calculating The Power of a Test in Hypothesis Testing with R
In hypothesis testing, the analyst has chance to commit both Type I and Type II errors. The Type I error (α) refers to the probability of wrongly rejecting a true Null hypothesis – H0, while the Type II error (ß) represents the probability that failing to reject a false H0. The value of 1- ß is called the Power of Test in hypothesis testing. Its value says the ability of correctly rejecting a false H0, under the specified Null hypothesis – H0 and Alternative hypothesis – H1.