What is Critical Value?

Critical values are essential components in hypothesis testing. They are calculated to help determine the significance of test statistics in relation to a specific hypothesis. The distribution of these test statistics guides the identification of critical values. In a one-tailed hypothesis test, there is one critical value, while in a two-tailed test, there are two critical values, each corresponding to a specific level of significance.

Critical Value Definition

Critical values are often defined as specific points on a scale used in statistical tests. These points help determine whether the results of a test are statistically significant or not. They serve as thresholds for making decisions about hypotheses being tested.

Critical Value

Critical value is a cut-off value used to mark the beginning of a region where the test statistic obtained in the theoretical test is unlikely to fail. Compared to the obtained test statistic to determine the critical value at hypothesis testing, Null hypothesis is rejected or not. Graphically, the critical value divides the graph into an accepted and rejected region for hypothesis testing. It helps to check the statistical significance of the test statistics. So, critical values are simply the function’s output at these critical points.

In this article, we will learn more about the critical value, its formula, types, and how to calculate its value.

Table of Content

  • What is Critical Value?
  • Critical Value Formula
  • T-Critical Value
  • Z-Critical Value
  • F-Critical Value
  • Chi-Square Critical Value

Similar Reads

What is Critical Value?

Critical values are essential components in hypothesis testing. They are calculated to help determine the significance of test statistics in relation to a specific hypothesis. The distribution of these test statistics guides the identification of critical values. In a one-tailed hypothesis test, there is one critical value, while in a two-tailed test, there are two critical values, each corresponding to a specific level of significance....

Critical Value Formula

There are different formulas for calculating the critical value, depending on the distributional nature of the test statistic. Confidence intervals or significance levels can be used to determine a critical value....

T-Critical Value

T-test is used when the population trend is not observed and the sample size is less than 30. The t-test is conducted when the population data follow the Student t distribution. The t critical value can be calculated as follows....

Z-Critical Value

A ‘Z test’ is performed on a normal distribution when the population mean is known and the sample size is greater than or equal to 30. The critical value of Z can be calculated as follows....

F-Critical Value

The F test is commonly used to compare differences between two samples. The test statistic thus obtained is also used for regression analysis. The critical value of f is given as:...

Chi-Square Critical Value

The chi-square test is used to check whether the sample data are consistent with the population data. It can also be used to compare two variables to see if they are correlated. The critical chi-square value is given as:...

Solved Questions on Critical Value

Question 1: Find the critical value for a right-tailed t-test with a sample size of 15 and α = 0.025....

Practice Problems on Critical Value

P1. A study examines if a new pain medication provides faster pain relief compared to a placebo. They use a one-tailed test with [Tex]\alpha[/Tex] = 0.05. Assuming a large enough sample size for normality, what is the critical value from the z-distribution?...

Conclusion

The significance value is an important aspect of statistical hypothesis testing and is a requirement that the hypothesis based on sample data may not be rejected. When informed decisions are made, appropriate logic and the use of critical criteria are necessary to control Type I errors, ensure the validity of statistical inferences, facilitate comparison across studies, and increase both the rigor and reliability of statistical analysis in the evaluation and decision-making process....

FAQs on Critical Value

What is the most important advantage of hypothesis testing?...