Python

One sample t-test: Definition, Formula, and Examples

This tutorial provides the definition of one sample t-test, the formulas of one sample t-test, examples of manual calculation. Definition and examples of One sample t-test One sample t-test is used to determine whether a mean is different from a specific value. You can calculate a mean based on a sample and compare whether the … Read more

Understanding Interaction Effects in Data Analysis

This tutorial introduces the basic idea of interaction effects in data analysis. This tutorial includes what an interaction effect is, examples of an interaction effect, and the statistical methods to do the analysis. What are interaction effects? (The definition) An interaction effect is when the effect of one variable (e.g., X) on another variable (e.g., Y) is … Read more

How to download CSV files from GitHub

This short tutorial shows how you can download CSV files from GitHub. Note that, this is different from read csv files from GitHub (for that, please refer to my other tutorial). Step 1: Right Click “Raw” First, you can go to a GitHub page with the CSV file and then right click the “raw” (see … Read more

How to Get Current Weekday in Python

This tutorial shows how you can get the current weekday in Python with 2 examples. Method 1: use weekday() Method 2: use isoweekday() Examples of getting current weekday in Python Example 1 for method 1 We can also check which weekday it is using weekday(). It returns the day of the week as an integer, … Read more

How to Interpret Interaction Effects in Linear Regression (4 Steps)

This tutorial shows how to interpret interaction effects in linear regression models. In summary, there are two perspectives, (a) mean difference perspective and (b) slope difference perspective. Interpret Interaction Effect in Linear Regression (a) Mean Difference Perspective: One way to interpret interaction effects in linear regression is based on mean differences. A significant interaction means … Read more

How to Avoid Including Dataframe Index when Saving as CSV file in Python

To avoid including the index column when saving as a CSV file, you can add index=False in df.to_csv() to avoid including the index clumn when saving a Python Pandas dataframe as a CSV file. df.to_csv(‘filename.csv’, index=False) Output: brands models 0 Tesla Model 3 1 Toyota RAV4 The following code with index=False is not to include … Read more

How to Convert 2-D Arrays to 1-D Arrays

There are 3 methods to convert 2-D arrays to 1-D ones in Numpy. The following shows the key syntax. Method 1: numpy.ravel() Method 2: ndarray.flatten(order=’C’) Method 3: ndarray.reshape(-1) Example 1 (Method 1): We can use numpy.ravel() to convert 2-D arrays to 1-D ones. Below is the example. Output: 2-D array: [[ 5 2 3 4 … Read more

How to Fix: Data must be 1-dimensional

You might encounter the following error when trying to convert Numpy arrays to a pandas dataframe. Exception: Data must be 1-dimensional 1. Reproduce the Error Output: Exception: Data must be 1-dimensional 2. Why the Error Happens It happens because pd.DataFrame is expecting to have 1-D numpy arrays or lists, since it is how columns within … Read more

How to Fix: if using all scalar values, you must pass an index

This tutorial shows how to fix the error when using Pandas. if using all scalar values, you must pass an index You encounter this error because you are trying to create a dataframe with all scalar values, but without adding index at the same time. Reproduces the Error Output: ValueError: If using all scalar values, … Read more