Question

You are taking a multiple-choice examination that has 20 questions in a particular section with 5 possible answers for each question. You did not study for the test and you guessed the answers. The probability that you guessed 50% of the answers correct by guessing is

A:- 0.02%

B:- 0.26%

C:- 30.5%

D:- 0.99%

Which of the following statement is true?

A:- A binomial distribution with n=20 and p =0.05 will be right-skewed.

B:- A binomial distribution with n=6 and p= 0.50 will be symmetric.

C:- A binomial distribution with n=20 and p=0.05 has an expected value equal to 1.

D:- a,b, and c are all true.

Answer 1

Solution:

Option A:- 0.02%

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a) True, because for p < 0.5, the binomial distribution is right skewed and for p > 0.5, the binomial distribution is left skewed.
b) True, at p = 0.5, binomial distribution is symmetric
c) True, Expected value = 0.05 * 20 = 1

d) True, a,b, and c are all true.