Test Statistic Calculator
Calculate test statistics for various hypothesis tests
Z-Test
Population mean
T-Test
Sample mean
Chi-Square Test
Variance
Z-Test Parameters
T-Test Parameters
Chi-Square Test Parameters
Interpretation
The test statistic measures how far your data is from the null hypothesis. Compare it to critical values to make a decision about your hypothesis.
When we run a hypothesis test, the result we rely on is called the test statistic. This number shows how far the sample result is from the value we are testing. A hypothesis test calculator does all the hard work for us. Instead of solving long formulas, you only need to enter the data, and the calculator will show the test statistic and p-value in seconds.
What Does Test Statistic Mean?
The test statistic is a number that compares your sample with what the null hypothesis says. If the number is close to what we expect, the null may still be true. But if the number is far away, it gives us a reason to doubt the null hypothesis.
In simple words, the test statistic tells us whether the sample result is normal or unusual under the null.
Why Use a Calculator?
Doing hypothesis testing by hand can be slow. A calculator helps by:
- Giving the test statistic quickly
- Showing the p-value
- Saving time when working with large data
- Reducing mistakes in manual work
This makes the tool useful for students, teachers, and anyone doing research.
Types of Test Statistics
Different tests use different formulas. A good hypothesis test calculator will handle many of them.
Z Test
Used when the sample size is large or the population variance is known.
Z=Xˉ−μ0σ/nZ = \frac{\bar{X} \mu_0}{\sigma/\sqrt{n}}Z=σ/nXˉ−μ0
Here:
- Xˉ\bar{X}Xˉ = sample mean
- μ0\mu_0μ0 = hypothesized mean
- σ\sigmaσ = population standard deviation
- nnn = sample size
T Test
Used for small samples when the variance is not known.
t=Xˉ−μ0s/nt = \frac{\bar{X} \mu_0}{s/\sqrt{n}}t=s/nXˉ−μ0
- sss = sample standard deviation
- Degrees of freedom = n−1n 1n−1
Proportion Test
Checks if a sample proportion is equal to a given population proportion.
Z=p^−p0p0(1−p0)/nZ = \frac{\hat{p} p_0}{\sqrt{p_0(1 p_0)/n}}Z=p0(1−p0)/np^−p0
- p^\hat{p}p^ = sample proportion
- p0p_0p0 = hypothesized proportion
- nnn = sample size
Chi-Square Test
Used for counts and categories.
χ2=∑(O−E)2E\chi^2 = \sum \frac{(O E)^2}{E}χ2=∑E(O−E)2
- OOO = observed values
- EEE = expected values
F Test
Used in regression and variance tests.
F=MSRMSEF = \frac{MSR}{MSE}F=MSEMSR
- MSR = mean square regression
- MSE = mean square error
One Tailed vs Two Tailed Tests
- One tailed test calculator: Checks only one direction (greater than or less than).
- Two tailed test calculator: Checks both directions (different in any way).
The type of test changes the way the test statistic is compared with critical values.
How to Use a Hypothesis Test Calculator
- Select the type of test (Z, T, proportion, etc.).
- Enter your data values.
- Enter the hypothesized value from the null.
- The calculator gives:
- Test statistic
- P value
- Decision on the null hypothesis
- Test statistic
This way, you don’t need to memorize every formula.
Significance Level and the Test Statistic
The significance level (α) is the cutoff for deciding. For example:
- If p-value < α, reject the null.
- If p-value> α, do not reject the null.
Common α values are 0.05 (5%) or 0.01 (1%).
Why Online Tools Are Helpful
- Simple to use
- Reduces calculation errors
- Saves time for learning and analysis
- Works for many test types
- Gives step by step results
FAQs
What is a test statistic in simple words?
It is a number that shows how far the sample is from the expected value.
Why use a hypothesis test calculator?
It saves time, reduces mistakes, and gives both the test statistic and p-value quickly.
Which test uses the Z statistic?
The Z test is used for large samples or when the population variance is known.
What is the T statistic used for?
It is used for small samples when the variance is unknown.
Can I do both one tailed and two tailed tests with a calculator?
Yes, most calculators allow both options.
Final Words
The test statistic is the key value in hypothesis testing. Without it, we cannot judge if the sample supports or rejects the null hypothesis. A hypothesis test calculator makes this work fast, clear, and accurate. Instead of long math, you get instant answers and can focus on understanding what your results mean.