Question

Kirsten calculated the mean of 10 quiz scores. Later she was told there was an error in grading one of her quizzes. A quiz score of 79 was revised to 89.

How will this grading revision affect the calculated mean of Kirsten's quiz scores?

A. The mean will stay the same.
B. The mean will be 1 point higher.
C. The mean will be 5 points higher.
D. The mean will be 10 points higher.

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Answer 1

Answer:

So the first mean was 79,

Now mean = Sum of no. /no.

79=Sum/10

Sum=790.

Now she says one score was 89 instead of 79.

So the second sum will be,

790-79+89=800.

So, now the mean = 800/10=80.

So ans is B. The mean will be 1 point higher.