Critical Value Calculator (T & Z)
Critical value calculator is a useful tool to measure t value, z value, chi-square value as well as F and R value. Those days are gone when you needed to look in the tables and scan hundreds of values to find a corresponding value for your data.
You can use t critical value calculator to find any type of critical value. With a simple and compelling interface, our t table calculator makes it easy to perform calculations for calculating critical values for any kind of testing.
What is a critical value?
A critical value specifies the margin of error in a distribution graph when analyzing statistics. If a research statistic's absolute value is greater than the critical value, then a statistical sense denies an accepted hypothesis.
Critical value formula
The critical value formula is the standard equation for the probability.
p = 1 – α/2
Where alpha (α) represents the significance or confidence level, and p is the probability.
In this equation, the alternative hypothesis is considered as alpha. If this hypothesis is true, the null hypothesis is not accepted.
The critical value can be calculated as z score or t score if the distribution of a sampling range is usual or near to normal. You can use our f critical value calculator to find a critical value.
How to find t critical value?
To find the critical value of t, follow the below example.
Example:
The t value is calculated by using the t distribution table. Let's assume degree of freedom as 4, alpha level of 0.025 and conduct a right-tailed test.
In the t distribution table given below, search for the degrees of freedom and its parallel alpha level. The critical value will be found at the intersection of a row and column.
| df | α = 0.1 | 0.05 | 0.025 | 0.01 | 0.005 |
| ∞ | ta= 1.2816 | 1.6449 | 1.96 | 2.3263 | 2.5758 |
| 1 | 3.078 | 6.314 | 12.706 | 31.821 | 63.656 |
| 2 | 1.886 | 2.920 | 4.303 | 6.965 | 9.925 |
| 3 | 1.638 | 2.353 | 3.182 | 4.541 | 5.841 |
| 4 | 1.533 | 2.132 | 2.776 | 3.747 | 4.604 |
| 5 | 1.476 | 2.015 | 2.571 | 3.365 | 4.032 |
For the alpha level 0.025, and degrees of freedom 4, the critical value of t will be 2.776.
T critical value = 2.776.
Moreover, you can use our t value calculator to find the t value at one click.
How to find z critical value?
Example:
We will assume significance level (α) of 0.03 to find the z critical value for two tailed test.
Step 1: Divide the significance level by 2.
α/2 = 0.03/2
α/2 = 0.015
Step 2: Calculate (1 - α/2).
1 - α/2 = 1 – 0.015
1 - α/2 = 0.985
Step 3: Look for 0.985 in z table. Add the corresponding value of first row and most left (first) column.
2.1 + 0.07 = 2.17
Z value = ± 2.17
Use z critical value calculator if you are not into prolonged calculations.
What is Chi-Square Value?
One way to show a relationship between two categorical variables is a Chi-square statistic.
The chi-square statistic compares two different variables to determine whether they are related. The numbers are determined by looking at the Chi-square table. Our chi square critical value calculator above eliminates the need to look for values in the tables.