Question

what role does significant value and significant level play in accepting or rejecting the null hypothesis?

Answer 1

A hypothesis test evaluates two mutually exclusive statements about a population to determine which statement is best supported by the sample data. A test result is statistically significant when the sample statistic is unusual enough relative to the null hypothesis that we can reject the null hypothesis for the entire population.

The common alpha values of 0.05 and 0.01 are simply based on tradition. For a significance level of 0.05, expect to obtain sample means in the critical region 5% of the time when the null hypothesis is true.

Using these tools to decide when to reject the null hypothesis increases your chance of making the correct decision.