Score Test Calculator

Run flexible score tests with guided statistical inputs. Compare null values, tails, and confidence settings. Interpret z statistics, p values, and decisions with confidence.

Score Test Inputs

Choose a score-test family, add your numbers, and review the decision, p value, interval, and assumptions.

Example Data Table

ScenarioInputsIllustrative output
One-sample proportionx = 62, n = 100, p₀ = 0.50, two-sided, 95%Z ≈ 2.400, p ≈ 0.016, reject H₀
Two-sample proportionsx₁ = 70, n₁ = 120, x₂ = 48, n₂ = 110, two-sided, 95%Z ≈ 2.269, p ≈ 0.023, reject H₀
One-sample meanx̄ = 53.4, μ₀ = 50, σ = 8, n = 36, right-tailed, 95%Z ≈ 2.550, p ≈ 0.005, reject H₀

Formula Used

One-sample proportion: z = (p̂ − p₀) / √[p₀(1 − p₀) / n]

Two-sample proportions: z = (p̂₁ − p̂₂) / √[p̂(1 − p̂)(1/n₁ + 1/n₂)] where p̂ is the pooled proportion under the null.

One-sample mean with known sigma: z = (x̄ − μ₀) / (σ / √n)

The p value comes from the standard normal distribution using the selected tail. Confidence intervals are included for practical interpretation.

How to Use This Calculator

  1. Choose the score test type that matches your study design.
  2. Select a two-sided, left-tailed, or right-tailed alternative.
  3. Enter the relevant sample counts, means, sizes, and null value.
  4. Set the confidence level used for the interval output.
  5. Click the calculate button to view results above the form.
  6. Review the z statistic, p value, interval, and decision.
  7. Use the CSV or PDF buttons to export your result table.
  8. Confirm assumptions before using the result in reports.

Frequently Asked Questions

1. What does a score test measure?

A score test checks whether observed data are compatible with a null parameter value. It uses information evaluated under the null hypothesis and reports a z statistic and p value.

2. When should I use a one-sample proportion score test?

Use it when you want to compare an observed success rate against a benchmark proportion, such as a defect rate, click rate, approval rate, or response rate.

3. Why does the two-sample proportion test use a pooled proportion?

Under the null hypothesis of equal proportions, both groups are assumed to share one common underlying probability. The pooled estimate reflects that shared value when computing the score statistic.

4. Is this the same as a Wald test?

No. A score test evaluates curvature and slope under the null. Wald tests center on the sample estimate instead. Score tests often behave better near boundaries or smaller samples.

5. What assumptions matter most?

You need independent observations, a suitable design, and adequate sample size for normal approximation. For mean tests, the population sigma must be known and the sampling model should be appropriate.

6. How do I interpret a p value here?

The p value is the probability of getting a test statistic at least as extreme as the observed one, assuming the null hypothesis is true.

7. Why include confidence intervals if the test already gives a decision?

A decision tells you whether evidence crosses a threshold. The interval adds magnitude and uncertainty, helping you judge whether the estimated effect is practically important.

8. Can I use this calculator for very small samples?

Be careful. Very small samples can weaken the normal approximation used by score tests. In such cases, exact methods or alternative modeling approaches may be more appropriate.