A null hypothesis can only be rejected at the 5% significance level if and only if:

(A) a 95% confidence interval includes the hypothesized value of the parameter

(B) a 95% confidence interval does not include the hypothesized value of the parameter

(C) the null hypothesis is void

(D) the null hypotheses includes sampling error

Option (B) a 95% confidence interval does not include the hypothesized value of the parameter

Step-by-step explanation:

Alpha, α = 0.05

We conduct a hypothesis test at 5% significance level.

The null hypothesis will be rejected when

Option (B) a 95% confidence interval does not include the hypothesized value of the parameter

When a 95% confidence interval is constructed, it contains all the possible values for the parameter being estimated. If the value of the parameter stated in the null hypothesis is contained in the 95% confidence interval, then we fail to reject the null hypothesis 0.05 level and accept it. If the value stated in the null hypothesis is not in the interval, then we fail to accept the null hypothesis and reject the null hypothesis at the 0.05 level.