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?\na it will decrease by 8.5.\nb it will increase by 13.5.\nc it will increase by 17.5.\nd it will decrease by 13.5.\ne it will decrease by 17.5.
Answer
Explanation:
Step1: Calculate the original mean
The original scores are 86, 84, 90, 90. The sum of these scores is $86 + 84+90 + 90=350$. There are 4 scores, so the original mean $\bar{x}_1=\frac{350}{4}=87.5$.
Step2: Calculate the new mean
The new set of scores is 86, 84, 90, 90, 0. The sum of these scores is $86 + 84+90 + 90+0 = 350$. There are 5 scores, so the new mean $\bar{x}_2=\frac{350}{5}=70$.
Step3: Find 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 less than the original mean, the mean decreases by 17.5.
Answer:
E. It will decrease by 17.5