There are 2 variables in this problem. One variable is the class number and other variable is the participation in extracurricular activities. Each variable has further two categories. There are two classes: Class 10 and 11. And students either participate or do not participate in extracurricular activities, which makes 2 categories.
The best approach to solve this question is to build a table and start entering the given information in it. When the given data has been entered fill the rest on basis of the data you have.
18 students from grade 11 participate in at least one Extracurricular activities. This means the rest students i.e. 22 students from grade 11 do not participate in Extracurricular activities.
32 students from grade 10 participate in at least one Extracurricular activities. This means total students who participate in at least one Extracurricular activities are 18 + 32 = 50 students.
The rest 50 students do not participate in at least one Extracurricular activities. From these 22 are from class 11. So the rest i.e. 28 are from class 10.
X+8y=18
-5x+3y=-4
Multiply the first equation by 5
Add the two equations together
5x+40y=90
-5x+3y=-4
43y=86
Y=2
Plug y into one equation to find x
X+16=18
X=2
Statistic significance requires that your sample be representative of the population, but I'm struggling with this because if the class is an elective then the answer would be: <span>No, it is not a valid inference because she asked all 22 students in her science class instead of taking a sample of the students in her school.
BUT if the class is required, as most science classes are, then it WOULD be a random sample of the school. So the last option would be correct.
My guess though is that the teacher is looking for answer B.
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The answer to your question is 57.6
