Answer:
0.0139
Step-by-step explanation:
Given that in a test for extrasensory perception, the experimenter looks at cards containing either a star, circle, wave, or square. (The subject cannot see the cards.)
Probability for guessing a correct shape out of 4 shapes = 0.25
Each trial is independent of the other
Hence X no of correct guesses is binomial with n = number of cards = 20 and p = constant probability =0.25
the probability a subject correctly guesses at least 10 of the 20 shapes
=, where F represents the cumulative probability upto 9
= 0.0139