A fast food restauranthas been considering dropping the pickles from its burgers. There is some sentiment that the ubiquitous pickle adds to the cost of the sandwich, but most people remove them anyway. The CEO decides that if we can be reasonably certain more than two-thirds of customers remove the pickle, then the pickle should no longer be placed on the sandwich (except by request).The operation managerwas enlisted to spy on a random sample of one thousand customers. He found that 70percent removed the pickle.

If the management wants to use confidence interval concept, to decide what they should do:

In what percentage of confidence level below that we canNOTbe sure that more thantwo-thirds of customers remove the pickle?