Question

A blind taste test is done to compare Cola 1 and Cola 2. Among n = 130 participants, p̂ = 0.68 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 statistic (z-score) for the sample proportion observed in the taste test. (Give the answer to three decimal places.)
z =

You may need to use the appropriate table in the Appendix of Tables to answer this question.

Answer 1

Test statistic,
z = (pcap - p)/sqrt(p*(1-p)/n)
z = (0.68 - 0.5)/sqrt(0.5*(1-0.5)/130)
z = 4.105