The alternative hypothesis is that there is evidence that the medicine relieves pain in less than 390 seconds on average.
In hypothesis testing, the null hypothesis (usually denoted as H₀ represents the status quo or the default assumption, while the alternative hypothesis (usually denoted as H₁ represents a claim or assertion that contradicts the null hypothesis. In this case, the null hypothesis might be that the average time for the medicine to relieve pain is 390 seconds or more.
The alternative hypothesis would then be that the average time is less than 390 seconds. In summary, the alternative hypothesis is that there is evidence that the medicine relieves pain in less than 390 seconds on average.