JavaScript Program for Chi-Square Critical Value Calculator

In this article, we will discuss the Chi-Square Critical Value Calculator. The Chi-Square Critical Value Calculator is a JavaScript tool used to determine critical values from the chi-square distribution. Chi-Square critical values help you decide if your study results are strong enough to conclude that there’s a real difference or if it might just be due to random luck.

These are the following approaches by using these you can calculate the chi-square critical value:

Using jStat library

• In this approach, we are using jStat to solve this problem.
• The ‘getCriticalValue’ function has a predefined value for the degree of freedom and significance level
• The result is printed in the console.

To run this code you have to install jSate library:

npm install jState

To run this code in your code editor:

node your_file_name

Example: This example shows the use of the above-explained approach.

Javascript

// Include the jStat library

// Javascript Function to calculate
//  the Chi-Square critical value
function getCriticalValue(DOF, SL) {

    const criticalValue =
        jStat.chisquare.inv(1 - SL, DOF).toFixed(4);
    console.log(`Chi-Square Critical Value: ${criticalValue}`);
}
// Replace with your
// degrees of freedom = DOF
const DOF = 4;
// Replace with your significance = SL
// level (e.g., 0.05 for 5%)
const SL = 0.05;
// Call the function to
//calculate the critical value
getCriticalValue();

Output:

Chi-Square Critical Value: 9.4877

Using a Predefined Table

• In this approach we are creating a custom table for chi-square critical values.
• We are creating a function ‘getCriticalValue’ for calculation of critical value.
• We are using predefined values for looking the chi square critical value based on input DOF and SL.

Example: This example shows the use of the above-explained approach.

Javascript

// degreesOfFreedom = DOF
//significanceLevel = SL
// Define a table of Chi-Square critical values
const chiSquareCriticalValues = {
    1: { 0.01: 6.63, 0.05: 3.84, 0.10: 2.71 },
    2: { 0.01: 9.21, 0.05: 5.99, 0.10: 4.61 },
    //You can add more degrees
    // of freedom as needed
};

function getCriticalValue(DOF, SL) {
    //It will look for the critical
    //  value in the table
    const criticalValue =
        chiSquareCriticalValues[DOF][SL];
    return criticalValue;
}

// Replace with your degrees of freedom
const DOF = 2;
// Replace with your
// significance level (e.g., 0.03 for 3%)
const SL = 0.05;

const criticalValue = getCriticalValue(DOF, SL);
console.log(`Chi-Square Critical Value: ${criticalValue}`);

Output:

Chi-Square Critical Value: 5.99