[Solved] Who is ultimately responsible for the final form an ad takes? A) the graphic designer B) the creative director C) the media planner D) the art director E) the PR representative P-Value: The p-value is a measure in statistical hypothesis testing representing the probability of obtaining a result at least as extreme as the observed one, assuming the null hypothesis is true. Hypothesized Mean Difference: The presumed difference between the means of two populations or conditions being compared in a statistical hypothesis test. Two-Tail: A term used in statistics referring to the two-tailed test of significance that checks for the possibility of positive or negative differences. Observations: The act of noting and recording something with instruments or the naked eye as part of a scientific or empirical study.