In hypothesis testing, which statement best describes the null hypothesis?

In hypothesis testing, which statement best describes the null hypothesis?

• A. H0 states there is a real effect.
• B. Ha states there is an effect or difference.
• C. H0 states there is no difference.
• D. H0 states no effect or status quo; Ha states there is an effect or difference.

Answer: (D)

In hypothesis testing, the null hypothesis represents the default assumption of no effect or no difference—essentially the status quo. We treat this as true unless the data provide strong evidence against it. The alternative hypothesis expresses what we aim to show: that there is an effect or a difference. So the best description is that the null states no effect or status quo, while the alternative states there is an effect or difference. This setup lets us measure how unlikely the observed data would be if the null were true and decide whether to reject it.

In hypothesis testing, the null hypothesis represents the default assumption of no effect or no difference—essentially the status quo. We treat this as true unless the data provide strong evidence against it. The alternative hypothesis expresses what we aim to show: that there is an effect or a difference. So the best description is that the null states no effect or status quo, while the alternative states there is an effect or difference. This setup lets us measure how unlikely the observed data would be if the null were true and decide whether to reject it.