Question

The fifth period Coordinate Algebra class received their quiz grades back from Mr. Smith today. The students were offered a chance for five quiz points if they constructed a box and whisker plot using the 20 quiz scores. As Mr. Smith's teaching assistant, you are asked to create a solution key for the box and whisker plot. Mr. Smith asked you to report back to him tomorrow morning with the Q1, Q3, and IQR.Use the set of student quiz scores to complete your calculations. Complete your work in the space provided or upload a file that can display math symbols if your work requires it.Turn in the Q1, Q3, and IQR and all of the necessary steps that you took to make your calculations. Fifth Period Quiz Grades: 100, 96, 58, 95, 60, 95, 69, 88, 71, 95, 85, 93, 91, 78, 78, 85, 86, 98, 87, 100

Answer 1

First, we need to put the numbers in order...
58,60,69,71,78,78,85,85,86,87,88,91,93,95,95,95,96,98,100,100
and since there is an even number of numbers (20), we need to find the 2 middle numbers and divide them by 2 to find the median (Q2)
Q2 (the median) = (87 + 88) / 2 = 175/2 = 87.5
now we take all the numbers below 87.5...and find the median (middle number) and that number will be Q1...there is 2 middle numbers...so we add them and divide by 2
Q1 = (78 + 78) / 2 = 156/2 = 78
now we take all the numbers after 87.5....and find the median...there will be 2 numbers, so we add them and divide by 2..that wil be Q3
Q3 = (95 + 95) / 2 = 190/2 = 95

So in summary :
Q1 = 78 <==
Q2 = 87.5 
Q3 = 95 <==

The interquartile range (IQR) is found by subtracting Q1 from Q3.
IQR = 95 - 78 = 17 <==