Question

A researcher is trying to show evidence for extra-sensory perception (ESP). She performs a test in which the subject is asked 10 yes or no question whose answer depends on information which the subject has not observed. Suppose that for each test, in the absence of ESP, the subject gets each question correct with 50% probability a) In the absence of ESP, what is the probability that a given test subject will answer at least 8 out of 10 questions correctly

Answer 1

Answer:

The answer is "0.0547".

Step-by-step explanation:

$P(Correct) = 0.50\\\\n = 10\\\\x = 8$

Using the binomial distribution:

$\to P(x,n) = n_{C}_x \times p^x \times (1-p)^{(n-1)}\\\\\to P(x \geq 8) = 1 - P( \leq 7)$

Calculating the excel formula:

$=BINOM.DIST(7,10,0.50,TRUE)$

$\to P(x \geq 8) = 1 - 0.9453\\\\ \to P(x \geq 8) = 0.0547$