Answer to Question #337651 in Statistics and Probability for shimmy

Question

For items 9 to 10, refer to the given table below.

Mathematics Quiz Scores of 15 Grade-10 Aphrodite Student

Name Score

Amy 17

Michelle 17

Aila 17

Evan 11

Albert 11

D-anne 16

Sarah 15

Isaac 18

Aidan 19

Carl 12

Cherry 17

Jethro 14

Angelo 16

Nica 18

Noah 15

9. If 1 is 12, how many students belong to the lowest 25%?

10. If 5 is 16, how many students belong to the lower 50%?

Answer 1

9 -- If $Q_1$ (the first quartile) is 12 it means that all students whos scores are lower than 12 belong to the lowest 25% (including the score 12). There are 3 students who have scores lower than 12 or 12.

10 -- If $D_5$ (the fifth decile) is 16, it means that students whos scores are under 16 belong to the lowest 50% (including the score 16). There are 8 students who have scores lower than 16 or 16.