1.44 Make-up exam: In a class of 28 students, 27 of them took an exam in class a

Question

1.44 Make-up exam: In a class of 28 students, 27 of them took an exam in class and 1 student took a make-up exam the following day. The professor graded the first batch of 27 exams and found an average score of 79 points with a standard deviation of 6.5 points. The student who took the make-up the following day scored 63 points on the exam.

a) Does the new student's score increase or decrease the average?

Decreases

Increases

b) The new average is: (round to two decimal places)

c) Does the new student's score increase or decrease the standard deviation of the scores?

Decreases

Increases

Explanation / Answer

a) Since the new score is less than the average score, it will decrease the average.

b) Sum of 27 scores = 27*79

Hence,

New average = (79*27 + 63)/28 = 78.43

c) Since the variability would increase in the overall data, the standard deviation increases.

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