Final answer:
To find the p-value for the given statistics, one would use a hypothesis test. Without a specific test statistic, we can't compute a p-value, but generally, if the p-value is greater than 0.05, we do not reject the null hypothesis.
Step-by-step explanation:
To find the p-value for n=23 with a difference in mean of 12.5 and standard deviation (sd) of difference 13.9, you would typically use a t-test or a z-test, depending on whether the population standard deviation is known or not. However, the provided information is somewhat disconnected and doesn't provide a clear test statistic from which to calculate the p-value directly. The null hypothesis being tested here usually assumes that there is no difference, indicating a mean difference of zero.
Given a significance level (alpha) of 0.05, if the computed p-value is greater than alpha, we would not reject the null hypothesis, as there's insufficient evidence to support a significant difference. The conclusion would be that, at the 5 percent level, there is insufficient evidence to conclude that there is a significant difference from the null hypothesis.