All euros have a national image on the "heads" side and a common design on the "tails" side. Spinning a coin, unlike tossing it, may not give heads and tails with equal probabilities. Polish students spun the Belgian euro 280 times, with its portly king, Albert, displayed on the heads side. The result was 160 heads. How significant is this evidence against equal probabilities? Follow the four-step process. (Round your test statistic to two decimal places and your P-value to four decimal places.) I have no idea what equation to use! Help please!
z = 1 P-value = 2