Answer: A. 85.7
Step-by-step explanation:
Given : Two sections of a class took the same quiz.
Section A had 15 students who had a mean score of 80, and Section B had 20 students who had a mean score of 90.
We know that , 
Then , for section A :
Similarly in Section B, 
Total scores = Sum of scores in sec A+Sum of scores in sec B
=1200+1800=3000
Total students = Students in sec A +Students in sec B
=15+20=35
Now , the mean score for all of the students on the quiz =
Hence, the approximate mean score for all of the students on the quiz = 85.7
Thus , the correct answer is option A. 85.7.
Using it's concept, the standard deviation of the data is of 3.742.
<h3>What are the mean and the standard deviation of a data-set?</h3>
- The mean of a data-set is given by the <u>sum of all values in the data-set, divided by the number of values</u>.
- The standard deviation of a data-set is given by the square root of the <u>sum of the differences squared between each observation and the mean, divided by the number of values</u>.
For this data-set, the mean is:
M = (1 + 4 + 4 + 4 + 4 + 6 + 5)/7 = 4.
Hence the standard deviation is:
More can be learned about the standard deviation of a data-set at brainly.com/question/12180602
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Area = πr² = π(8)² = 201.06 in²
Answer: 201.06 in²
D
You figure out the absolute value by determining how far the number is from the point 0 on a number line.
