Answer:
The answer is actually D
Explanation:
This is true because when you add the scores together you get 350 and then you divide that number by however many data numbers there are in the set.
86+84+90+90=350
because there are 4 numbers in the data set you so divide 350 by 4 which equals 87.5
Then he scores a 0 on the quiz, it will indeed affect the mean.
You add the numbers 86+84+90+90+0 still equals 350, however, instead of 4 numbers in the data set it's 4 because of the zero.
Instead of dividing by 4, you divide by 5
350 divided by 5 equals 70.
the original MEAN was 87.5 and now it is 70, so that means that it decreased by 17.5. there's is your answer. The answer is D 17.5