Question

Mr. Evans displays the test scores of his first period class in the box plot below.

Answer 1

I think it is the last one, have a nice day!

Answer 2

Answer:  Third option is correct.

Step-by-step explanation:

Since we have given that

1st Quartile of 3rd class period = 78

For 1st class period,

1st Quartile = 70

3rd Quartile = 85

IQR = Q₃-Q₁

$IQR=85-70\\\\IQR=15$

According to question,

IQR of 3rd class period is one - third of the IQR of 1st class period.

So, it becomes

$IQR_3=\dfrac{1}{3}\times IQR_{1}\\\\IQR_3=\dfrac{1}{3}\times 15\\\\IQR_3=5$

Now, we need to find the value of 3rd quartile of the scores from 3rd period.

$IQR_3=Q_3-Q_1\\\\5=Q_3-78\\\\5+78=Q_3\\\\Q_3=83$

Hence, Third option is correct.