ripleys spelling grades are 86, 84, 90, and 90. if he scores 0 on the next spelling quiz, what will happen…

ripleys spelling grades are 86, 84, 90, and 90. if he scores 0 on the next spelling quiz, what will happen to the mean of his scores? a it will decrease by 8.5. b it will increase by 13.5. c it will increase by 17.5. d it will decrease by 13.5. e it will decrease by 17.5.

ripleys spelling grades are 86, 84, 90, and 90. if he scores 0 on the next spelling quiz, what will happen to the mean of his scores? a it will decrease by 8.5. b it will increase by 13.5. c it will increase by 17.5. d it will decrease by 13.5. e it will decrease by 17.5.

Answer

Explanation:

Step1: Calculate the original mean

The original scores are 86, 84, 90, 90. The sum of the original scores is $86 + 84+90 + 90=350$. The number of original scores $n_1 = 4$. The original mean $\bar{x}_1=\frac{350}{4}=87.5$.

Step2: Calculate the new mean

The new scores are 86, 84, 90, 90, 0. The sum of the new scores is $86 + 84+90 + 90+0 = 350$. The number of new scores $n_2=5$. The new mean $\bar{x}_2=\frac{350}{5}=70$.

Step3: Calculate the change in the mean

The change in the mean is $\bar{x}_1-\bar{x}_2=87.5 - 70=17.5$. Since the new mean is smaller than the original mean, the mean decreases by 17.5.

Answer:

E. It will decrease by 17.5.