In statistics, hypothesis testing is a confirmatory analysis of statistical data to make yes or no decisions. A hypothesis test analyses the results of the null hypothesis and the alternative hypothesis of a population. If P-value is small, H0 will be rejected and if it is large p-values will not allow to reject the H0. P-value, Z score and hypothesis testing of a single population meant can be calculated using Hypothesis testing calculator for population mean.
If you are performing one tailed test which has a sample mean of 20 and population mean is 15. The size of the population is 5 and SD is 25 with the significance level of -10. If you perform the statistical hypothesis testing,
T-score is 0.44721
P-value is 0.6726
P-value > -10 ( Significance level). Hence, H0 is not rejected.H0 is Null Hypothesis.