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The null hypothesis includes the boundary value. In the example with a population mean of 23, the null hypothesis is centered around or includes this specific value as the reference claim against which the alternative hypothesis tests for departure.

Conditions: The example uses a population mean of 23.; The null hypothesis is formulated to include this value.

The null hypothesis includes the boundary value. In the example with a population mean of 23, the null hypothesis is centered around or includes this specific value as the reference claim against which the alternative hypothesis tests for departure.

Conditions: The example uses a population mean of 23.; The null hypothesis is formulated to include this value.

A one-tailed test allocates the entire significance level $\alpha$ to its designated tail. Unlike a two-tailed test which splits $\alpha$ into $\alpha/2$ for each tail, a one-tailed test places all of $\alpha$ in either the left or the right tail, depending on the direction specified by the alternative hypothesis.

Conditions: The test is one-tailed.; The significance level is $\alpha$.; The direction is specified by the alternative hypothesis ($<$ or $>$).

A one-tailed test allocates the entire significance level $\alpha$ to its designated tail. Unlike a two-tailed test which splits $\alpha$ into $\alpha/2$ for each tail, a one-tailed test places all of $\alpha$ in either the left or the right tail, depending on the direction specified by the alternative hypothesis.

Conditions: The test is one-tailed.; The significance level is $\alpha$.; The direction is specified by the alternative hypothesis ($<$ or $>$).