A professor believes that students perform better on an introductory statistics exam if they are only allowed one sheet of notes ("cheat sheet") compared to an "open book" exam (where they have access to all notes, textbook, etc.). To test his theory he randomly assigned the 50 students in his class to two groups: one group took the exam with just a "cheat sheet", and the other group took the same exam "open book". On average students in the "cheat sheet" group scored 6 points higher than the students in the "open book" group.

To test these hypotheses the professor uses a randomization test. He wrote the students' grades on 50 index cards, shuffled the cards and dealt them into two groups: cheat sheet and open book. He then recorded the difference between the two group averages (x ?cheat sheet ? x ?open book) and repeated 100 times. The dot plot below shows the null distribution of these differences (denoted as diffMean).

What is the p-value?

Select one:

a.0.12

b.0.06

c.0.03

d.Cannot be determined based on the given information.

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