A marketing survey is conducted in which students are to taste two different brands of soft drink. Their task is to correctly identify the brand tasted. A random sample of 200 students is taken. Assume that the students have no ability to distinguish between the two brands.

Answer from a previous question in this problem ----> the probability that the sample percentage is contained within the lower limit of 41.18% and 55.82%

There is a 90% probability that the sample percentage will be contained within ______________% symmetrically around the population percentage