Question

A quiz consists of 20 true-false questions. The score for each question is 1 point if it is answered correctly, and 0 otherwise. Suppose a student guesses the answer to Question 1 on the test by tossing a coin: if the coin lands Heads, she answers True, and if it lands Tails, she answers False. What is the chance that she gets the right answer?

Answer 1

Obvioulsy, 50 per cent of chances

Answer 2

obviously*

Answer 3

Could you please, elaborate? Thanks

Answer 4

well, how can I explain this... For the 1 question he only has 2 choices, one is true and the other is false. Okay. If he tosses the coin, he also only has two results, head or tail. Head - true and tail - false.

Answer 5

When he tosses the coin and the result is head, he will put true as an answer. So he only has two chances, give the correct answer or give the wrong answer.

Answer 6

Whatever the result of tossing the coin is, he will only put true or false, and by that he only has one chance of getteing it right of two possible results. Can not explain it better.

Answer 7

I think I understand it now, but if you were to express your answer in decimals, what would it be please?

Answer 8

0.5

Answer 9

Much appreciated; thank you.

Answer 10

Please, I have an additonal question for you. Would you say the events of guessing the right answers to questions (1) and (2) in the stated problem above are independent or dependent events? Thanks.

Answer 11

independet

Answer 12

Thank you.

Answer 13

I am sorry for taking more of your time, but I still have more question with respect to the stated problem. I have tried working it out, but I am obviously wrong in my answer. Here is the question: "To get an A grade on the test, you need a total score of more than 16 points. One of the students knows the correct answer to 6 of the 20 questions. The rest she guesses at random by tossing a coin (one toss per question, as in 4B). What is the chance that she gets an A grade on the test?". I have tried working it out like I said earlier but my answer is obviously wrong. I got 70%, and that is apparently not the right answer. Could you please, kindly help out? Thank you.