Premiers of children's movies are often accompanied by special promotional offers through one of the leading fast-food chains. During the many years that McDonald's
has run such promotions, the company has found that 15% of all its customers will
buy the specialty item. When Disney re-released its movie “Snow White and the
Seven Dwarfs” on DVD last year, McDonald's simultaneously initiated a promotional
offer enabling its customers to purchase a specially designed set of drink glasses
featuring each of the seven dwarfs. Halfway through the promotional period, a study
was performed at several restaurants throughout the country; 17.6% of the 500
customers sampled had purchased a set of these glasses. What was the probability of
having randomly sampled 500 customers and finding at least 17.6% of them had
purchased a set of the collectible glassware?