Amanager at a phone company wants to know if the company’s current customers would be interested in a new calling plan. which sampling method will most likely result in a biased sample? an office assistant selects every 50th name on a customer list. an office assistant divides the customers by time zone and randomly selects 100 customers in each zone. an office assistant programs a computer to randomly select 500 customers from its database. an office assistant selects the customers who call the office with questions about their current plan during one week

In a test for esp (extrasensory perception), a subject is told that cards only the experimenter can see contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has probability 0.25 of guessing correctly on each card. a. the count of correct guesses in 20 cards has a binomial distribution. what are n and p? b. what is the mean number of correct guesses in 20 cards for subjects who are just guessing? c. what is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?