A test consists of 10 true/false questions. To pass the test a student must answer at least 6 questions correctly. If a student guesses on each question, what is the probability that the student will pass the test? Round to three decimal places. A. 0.205 B. 0.172 C. 0.828 D. 0.377
Accepted Solution
A:
Answer: D. 0.377Step-by-step explanation:Given : The choices of answers for each question =2Then , the probability of choosing a correct option : p= 0.5Total number of question : n=10Also, to pass the test a student must answer at least 6 questions correctly. Let x be the random variable that represents the number of questions answered.Using binomial probability formula, to find the probability of getting success in x trials.[tex]P(x)=^nC_xp^x(1-p)^{n-x}[/tex]If a student guesses on each question, then s the probability that the student will pass the test :-[tex]P(x\geq6)=P(6)+P(7)+P(8)+P(9)+P(10)\\\\=^{10}C_6(0.5)^6(0.5)^4+^{10}C_7(0.5)^7(0.5)^3+^{10}C_8(0.5)^8(0.5)^2+^{10}C_9(0.5)^9(0.5)^1+^{10}C_{10}(0.5)^{10}\\\\=(0.5)^{10}(210+120+45+10+1)\\\\=0.376953125\approx0.377[/tex]Hence, the probability that the student will pass the test = 0.377