Statistics & Data Science · pattern F, Dataset
Enter a sample mean, hypothesised mean, standard deviation and sample size for the test statistic, the p-value and a conclusion phrased the way a marker expects to read it.
z = (x̄ − μ₀) ÷ (s ÷ √n)
A one-sample test of a mean against a hypothesised value, assuming the sampling distribution of the mean is approximately normal — reasonable above about thirty observations.
2.3373
Failing to reject the null is not evidence that the null is true. It means this sample did not provide enough evidence against it, which is a different and weaker statement.
The correct phrasing is that the null hypothesis is rejected or not rejected at a stated significance level, never that it is proved or disproved. Marks are routinely lost for writing that a test proves the alternative. State the hypotheses, the statistic, the p-value, the decision and the effect size — in that order — and the presentation criteria look after themselves.
If the number is not the part you are stuck on, that is what the service is for — a specialist who explains the working, not just the answer.
Statistical output here is for coursework and learning. Reported p-values and intervals assume the conditions stated on the page; nothing here checks whether those conditions hold for your data.