Hypothesis Testing Calculator

Run a one-sample z-test and get the decision.

z-statistic 2

Two-tailed p-value 0.0455

Decision at alpha 0.05 Reject H0

Formula: z = (mean - mu) / (sigma / sqrt(n))

Step-by-step with your numbers:

1. Values used:

2. Sample mean = 105

3. Null mean = 100

4. Population SD = 15

5. Sample size = 36

7. z-statistic = 2

8. Two-tailed p-value = 0.0455

9. Decision at alpha 0.05 = Reject H0

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A z-test checks whether a sample mean differs significantly from a hypothesized value.

The math behind it

z = (sample mean - null mean) / (sigma / sqrt(n)). If the two-tailed p-value is below alpha, reject the null.

mean 105, mu 100, sigma 15, n 36 gives z = 2, p about 0.046, reject H0.

What is the null hypothesis?

The default claim of no effect or no difference being tested against.