Question

Students collected data about the capacities of their lungs by inflating balloons with a single breath. they measured the circumference of the balloons in centimeters. each student completed three trials and calculated the average. balloon circumference (cm) student trial 1 trial 2 trial 3 average 1 66.0 66.5 68.5 67.0 2 67.5 64.0 70.5 67.3 3 60.3 60.5 60.5 61.0 4 55.0 58.0 59.0 57.3 which student miscalculated her average? 1. student 1 2. student 2 3. student 3 4. student 4

Answer 1

The given data is the following:

Student Trial 1  Trial 2 Trial 3 Average
-----------  --------  --------  --------  ------------
    1           66.0    66.5   68.5     67.0
    2          67.5     64.0   70.5     67.3
    3          60.3     60.5   60.5    61.0
    4          55.0     58.0   59.0    57.3

Let us check the reported averages.
Student 1:
Average = (66.0 + 66.5 + 68.5)/3 = 67.0   Correct
Student 2:
Average = (67.5 + 64.0 + 70.5)/3 = 67.3    Correct
Student 3:
Average = (60.3 + 60.5 + 60.5)/3 = 604    Incorrect
Student 4:
Average = (55.0 + 58.0 + 59.0)/3 = 57.3    Correct

Answer: Student 3

Answer 2

Look at the given data & calculate the average of each students data,

1) 66, 66.5, 68.5, 67
Average = $\frac{66+66.5+68.5}{3}$ = 67 CORRECT

2) 67.5 64.0 70.5 67.3
Average = $\frac{67.5+64+70.5}{3}$ = 67.3 CORRECT

3) 60.3 60.5 60.5 61.0
Average = $\frac{60.3+60.5+60.5}{3}$ = 60.43 INCORRECT

4) 55.0 58.0 59.0 57.3
Average = $\frac{55+58+59}{3}$ = 57.3 CORRECT



Therefore, 3. Student 3 is the correct answer.