A teaching assistant gives a quiz with 10 questions and no partial credit. After grading the papers, the TA writes down for each student the number of questions the student got right and the number wrong. The average number of right answers is 6.4 with an SD of 2.0; the average number of wrong answers is 3.6 with the same SD of 2.0. The correlation between the number of right answers and the number of wrongs is 0 −0.50 +0.50 −1 +1 can’t tell without the data. Explain.
A teaching assistant gives a quiz with 10 questions and no partial credit. After grading the papers, the TA writes down for each student the number of questions the student got right and the number wrong. The average number of right answers is 6.4 with an SD of 2.0; the average number of wrong answers is 3.6 with the same SD of 2.0. The
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Here the correlation between number of right answers and number of wrong answers can't be tell without data, because to calculate correlation we first have to calculate covariance which is based on all the data points of both variables.
So we need data to find correlation.
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