the mean quiz score for 8 students is 50. the scores for 7 of the 8 students are shown below. what is the…
the mean quiz score for 8 students is 50. the scores for 7 of the 8 students are shown below. what is the score for the remaining student? quiz scores
Answer
Explanation:
Step1: Calculate total score of 8 students
The mean score of 8 students is 50. Using the formula for the mean $\bar{x}=\frac{\sum_{i = 1}^{n}x_{i}}{n}$, where $\bar{x}$ is the mean, $n$ is the number of data - points, and $\sum_{i = 1}^{n}x_{i}$ is the sum of the data - points. For $n = 8$ and $\bar{x}=50$, the total score of 8 students is $n\times\bar{x}=8\times50 = 400$.
Step2: Calculate sum of 7 students' scores
From the dot - plot, the scores of 7 students are 20, 20, 30, 80, 80, 80. The sum of these scores is $20 + 20+30 + 80+80+80=310$.
Step3: Find the score of the 8th student
Let the score of the 8th student be $x$. We know that the sum of the scores of 8 students is 400 and the sum of the scores of 7 students is 310. So, $x=400 - 310=90$.
Answer:
90