2. An online bookstore is having a one-day sale. Softcover books are $4, hardcover books are $7, magazines are $3, and all digital downloads of books are $2.

Let's say 150 customers purchased books in one form or another that day. Below are the frequencies in which customers purchased books:

Books: Purchases:
Softcover 42
Hardcover 28
Magazine 23
Digital Download 57
Based on the data above, which is the correct relative frequency with discrete random variable X = "the amount of money for a book?"

In a test for esp (extrasensory perception), the experimenter looks at cards that are hidden from the subject. each card contains either a star, a circle, a wave, a cross or a square.(five shapes) as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. when the esp study described above discovers a subject whose performance appears to be better than guessing, the study continues at greater length. the experimenter looks at many cards bearing one of five shapes (star, square, circle, wave, and cross) in an order determined by random numbers. the subject cannot see the experimenter as he looks at each card in turn, in order to avoid any possible nonverbal clues. the answers of a subject who does not have esp should be independent observations, each with probability 1/5 of success. we record 1000 attempts. which of the following assumptions must be met in order to solve this problem? it's reasonable to assume normality 0.8(1000), 0.2(1000)%30 approximately normal 0.8(1000), 0.2(1000)% 10 approximately normal srs it is reasonable to assume the total number of cards is over 10,000 it is reasonable to assume the total number of cards is over 1000