Question

during her lunch hour, shawna asked 40 students how many after - school clubs they joined. the list below shows the number of clubs that the students joined.
2, 2, 3, 0, 3, 2, 4, 2, 1, 4, 3, 2, 4, 1, 0, 2, 1, 3, 2, 0,
1, 1, 2, 1, 0, 3, 0, 1, 4, 1, 1, 0, 2, 3, 2, 0, 3, 2, 0, 1
if this sample is representative of the student population of 360 students, about how many students in the school joined three clubs?
15 students
63 students
109 students
189 students

Explanation:

Step1: Count 3s in sample

Count the number of 3s in the sample of 40 students. There are 7 students who joined 3 clubs in the sample.

Step2: Set up proportion

Let $x$ be the number of students who joined 3 clubs in the population of 360 students. Set up the proportion $\frac{7}{40}=\frac{x}{360}$.

Step3: Solve proportion

Cross - multiply: $40x = 7\times360$. Then $x=\frac{7\times360}{40}=63$.

Answer:

63 students