Critical Chi-Square Value Calculator

Use this free calculator to compute the critical Chi-square (Χ2) value given right tail probability level and the degree of freedom.

Please input numbers in the required fields and click CALCULATE.

What Is The Critical Chi Square Value

In case you don’t know, the chi square statistic is used to compare two categorical variables to determine if they are related. When you are trying to calculate the chi square statistic, you can use our critical value chi square calculator. However, you will also need to take a closer look at the chi square table. 

One of the things that you need to keep in mind about the chi square table is that it is very similar to the other distribution tables. So, you will need to know not only the degrees of freedom but also the probability. In most cases, you won’t need to worry about determining either of these values since they are usually included in the question. 

Calculating The Critical Chi Square Value By Hand

While you can definitely use our free critical value chi square calculator located at the top of this page, we believe that it is important that you are aware of how you can determine this value by hand. So, all you need to do is to follow a couple of steps. 

Let’s imagine that you want to make an experiment in an agricultural firm. Say that the company wants to know if there is a link between cross strains of plants (hybrids) and the unwanted or unexpected plants (number of deviations) that can show up. 

This specific firm has two types of corn that they are crossing: the yellow and the blue corn. Most biologists tend to agree that deviations with a chance of probability of more than 5% are not statistically significant. 

So, to solve this problem, we will need to determine the critical chi square value. As we already mentioned, you can use our free critical value calculator chi square located at the top of this page.

Step #1: Determine the number of degrees of freedom

The first thing that you need to do to determine the critical chi square value is to determine the number of degrees of freedom. When the answer isn’t in the question that was provided then the degrees of freedom will be equal to the number of classes or categories minus 1. If you remember, the company crosses yellow and blue corn. So, this means that you have 2 categories. This means that:

Degrees Of Freedom = 2 – 1 = 1

Step #2: Determine the probability that the situation you are investigating would happen by chance

Now, on this step, you will need to know the probability which is usually stated in the question as well. If you get back at our example, you will immediately see that the probability if 5% or 0.05.

Step #3: Look up the degrees of freedom and the probability in the chi square table

All you need to do is to grab the value that has 1 degree of freedom and 0.05 probability in the chi square table. This number is 3.84. So, this is your critical value. You can also confirm this by using our critical value calculator chi square.