Chi-Square Test in R: Test Independence Between Variables (Step-by-Step + One-Liner) #R #Statistics

About this lesson

Learn how to perform the Chi-Square Test of Independence in R to analyze relationships between categorical variables. This tutorial explains contingency tables, expected frequencies, residual analysis, and interpretation of results. ✔ Create contingency tables ✔ Perform Chi-Square tests ✔ Interpret p-values and expected counts ✔ Visualize categorical relationships ✔ Interview-ready explanations Perfect for statistics learners, data analysts, and R programmers. # ----- Long Way Approach ----- # Step 1: Read dataset df v- read.csv("chisquare_data.csv") # Example columns: # gender -v Male/Female # purchase -v Yes/No # Step 2: Create Contingency Table cont_table v- table(df$gender, df$purchase) print(cont_table) # Step 3: Perform Chi-Square Test chi_test v- chisq.test(cont_table) print(chi_test) # Step 4: View Expected Frequencies chi_test$expected # Step 5: Check Standardized Residuals chi_test$residuals # Step 6: Visualize Data barplot(cont_table, col = c("skyblue","orange"), legend = TRUE) # ----- One-Liner Approach ----- # Chi-square test in one line chisq.test(table(read.csv("chisquare_data.csv")$gender, read.csv("chisquare_data.csv")$purchase)) In this tutorial, we learn how to perform the Chi-Square Test of Independence in R, a statistical method used to determine whether two categorical variables are related or independent. This test is widely used in survey analysis, marketing analytics, medical research, and behavioral studies. 📌 1. When to Use Chi-Square Test Use the Chi-Square test when: Both variables are categorical You want to check association between variables Example: Gender Purchased Male Yes Female No Question: 👉 Does gender influence purchasing behavior? 📌 2. Creating Contingency Table We first convert raw data into a frequency table. table(df$gender, df$purchase) Example output: Yes No Male 30 20 Female 25 35 This table becomes the input for Chi-Square testing. 📌 3. Running Chi-Squar

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