Any multiple choice test with a 19 questions, each question is for possible answers, one of which is correct. For students to guess it all answers, find the mean for the number of correct answers.

Answer 1

To find the mean for the number of correct answers, we need to consider the probability of getting each question correct.

Since each question has 4 possible answers, the probability of getting any one question correct by guessing is 1/4, or 0.25.

Now, let's calculate the mean for the number of correct answers:

Mean = Sum of (number of correct answers * probability of getting that number correct)
= (0 * probability) + (1 * probability) + (2 * probability) + ... + (19 * probability)

The probability mentioned above is 0.25.

Mean = (0 * 0.25) + (1 * 0.25) + (2 * 0.25) + ... + (19 * 0.25)

Mean = 0 + 0.25 + 0.5 + ... + 4.75

To find the sum of this arithmetic series, we can use the formula:

Sum = n/2 * (first term + last term)
= 19/2 * (0 + 4.75)
= 19/2 * 4.75
= 90.25

Therefore, the mean value for the number of correct answers in this multiple-choice test is 90.25.