Need help with this. In a test for ESP (extrasensory perception), the experiment
ID: 3155065 • Letter: N
Question
Need help with this. In a test for ESP (extrasensory perception), the experimenter looks a. cards.ha. arc hidden from the subject. Each card contains either a star, a circle, a wave, or a square. As the experimenter looks at each car s m turn, the subject names the shape on the card. If a subject simply guesses the shape on each card, what is the probability of a successful guess on a sing e car. Because the cards arc independent, the count of successes in 20 cards has a binomial distribution. What is the probability that a subject correctly guesses at least 10 of the 20 shapes? In many repetitions of this experiment with a subject who is guessing, how many cards will the subject guess correctly on the average? What is the standard deviation of the number of correct guesses?Explanation / Answer
a) Probability is 1/4=0.25 [ each card contains either circle, star, wave and sqaure)
b) P(X>=10)=1-P(X<10)=1-0.986=0.014
P(X=0)=20C0(0.25)^0(0.25)^20=0.003, compute remaining probabilities till P(X=9) and add them.