How to read the t boundary value table
In the field of statistics and data analysis, the t-bounded value table is a very important tool, especially in hypothesis testing and confidence interval calculation. This article will introduce in detail how to correctly view and use the t-boundary value table, and attach structured data examples to help readers quickly master this skill.
1. What is the t boundary value table?

The t-bounds table is a probability table for the t-distribution that provides critical values at different degrees of freedom (df) and significance levels (α). These critical values are used to determine whether the results of a statistical test are significant.
2. Structure of t boundary value table
The t-boundary value table usually consists of the following parts:
| Degrees of freedom (df) | Significance level (α=0.05) | Significance level (α=0.01) |
|---|---|---|
| 1 | 12.706 | 63.657 |
| 5 | 2.571 | 4.032 |
| 10 | 2.228 | 3.169 |
| 20 | 2.086 | 2.845 |
| 30 | 2.042 | 2.750 |
3. How to view the t boundary value table?
1.Determine degrees of freedom (df): The degrees of freedom are usually equal to the sample size minus 1 (n-1). For example, when the sample size is 10, the degrees of freedom are 9.
2.Choose significance level (α): Common significance levels are 0.05 and 0.01, corresponding to 95% and 99% confidence levels respectively.
3.Find critical value: Find the corresponding critical value in the table based on the degrees of freedom and significance level. For example, when the degrees of freedom are 5 and α=0.05, the critical value is 2.571.
4. Application examples of t boundary value table
Suppose we conduct a two-tailed t-test with a sample size of 16 (degrees of freedom = 15) and a significance level of 0.05. From the t boundary value table, we can find that the critical value is 2.131. If the calculated absolute value of the t-statistic is greater than 2.131, the null hypothesis is rejected.
| Degrees of freedom (df) | α=0.05 (two-tailed) | α=0.01 (two-tailed) |
|---|---|---|
| 15 | 2.131 | 2.947 |
| 20 | 2.086 | 2.845 |
| 25 | 2.060 | 2.787 |
5. Things to note
1.One-tailed and two-tailed tests:t-bounds tables usually provide critical values for two-tailed tests. If it is a one-tailed test, the significance level needs to be halved.
2.Degrees of freedom approximation: If the degrees of freedom are not listed directly in the table, you can take the nearest value or calculate it using interpolation.
3.software replacement: Modern statistical software (such as R, Python) can directly calculate the critical value of the t distribution, but it is still very important to understand the principle of the t boundary table.
6. Summary
The t-boundary value table is a basic tool in statistics. Proper use of it can help us make scientific statistical inferences. Through the introduction and examples of this article, I believe that readers have mastered how to view and use the t boundary value table. In practical applications, combining specific problems and data characteristics and flexibly using the t boundary value table will greatly improve the accuracy and efficiency of data analysis.
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