8. (2 points) A blind taste test is done to compare Cola 1 and Cola 2. Among n = 60 participants, p = 0.65 is the proportion preferring Cola 1. If, actually, the two colas are equally preferred in a larger population of tasters, p = 0.5 is the corresponding population proportion. Assuming that p = 0 5, find the value of the standardized z-statistic for the sample proportion in the taste test