Two-way tables: joint, marginal and conditional relative frequencies

Answer Key - Grade 9 Math Worksheet

Circle the best answer, or write your answer on the line.

1. Read this first

   Two-way table of students

   	Walks	Bikes	Bus	Total
   9th grade	26	13	25	64
   10th grade	10	25	11	46
   Total	36	38	36	110

2. 1.

   Ari sorted students in a two-way table. The crossing guard wants a copy. Of the students in the "9th grade" row, what percent walk to school, to the nearest whole percent?

   41
3. 2.

   Bo sorted students in a two-way table. The cooks are taking notes. Of the students in the "Late lunch" row, what percent choose salad, to the nearest whole percent?

   21

4. Two-way table of club members

   	Zoo	Museum	Aquarium	Total
   Science club	23	7	17	47
   Art club	19	12	26	57
   Total	42	19	43	104

5. 3.

   Esme sorted club members in a two-way table. Everyone wants the trip to be tomorrow. Of the club members in the "Science club" row, what percent vote for the aquarium, to the nearest whole percent?

   36

6. Two-way table of students

   	Math	Science	Art	Total
   Coding club	16	18	24	58
   Not in the club	9	6	8	23
   Total	25	24	32	81

7. 4.

   Jun sorted students in a two-way table. The club robot helped count. Of the students in the "Not in the club" row, what percent like math best, to the nearest whole percent?

   39

8. Two-way table of club members

   	Mystery	Comics	Nature	Total
   Reads at night	11	18	18	47
   Reads by day	26	23	29	78
   Total	37	41	47	125

9. 5.

   Kira sorted club members in a two-way table. The librarian is thrilled. Of the club members in the "Comics" column, what percent read at night, to the nearest whole percent?

   44

10. Two-way table of students

    	Walks	Bikes	Bus	Total
    9th grade	6	7	12	25
    10th grade	13	19	22	54
    Total	19	26	34	79

11. 6.

    Milo sorted students in a two-way table. The crossing guard wants a copy. Of the students in the "Bus" column, what percent are in 10th grade, to the nearest whole percent?

    65
12. 7.

    Noah sorted students in a two-way table. The cooks are taking notes. Of the students in the "Pizza" column, what percent have early lunch, to the nearest whole percent?

    61
13. 8.

    Pia's two-way table counts students. Is there a link between the grade and whether students walk to school?

    • Yes: 10th graders tend to walk to school more often than 9th graders.
    • Yes: 9th graders tend to walk to school more often than 10th graders.
    • Yes: more 10th graders walk to school, 36 against 22.
    • Yes: being in 9th grade makes students walk to school.
    • No: about the same share of each group tends to walk to school.
14. 9.

    Ren's two-way table counts students. Is there a link between being in the coding club and whether students like art best?

    • Yes: coding club members tend to like art best more often than other students.
    • Yes: being in the coding club makes students like art best.
    • Yes: other students tend to like art best more often than coding club members.
    • No: about the same share of each group tends to like art best.
    • Yes: more other students like art best, 12 against 10.

15. Two-way table of club members

    	Mystery	Comics	Nature	Total
    Reads at night	35	33	30	98
    Reads by day	17	35	23	75
    Total	52	68	53	173

16. 10.

    Zee's two-way table counts club members. Is there a link between when members read and whether club members like nature books best?

    • Yes: more night readers like nature books best, 30 against 23.
    • Yes: being a night reader makes club members like nature books best.
    • No: about the same share of each group tends to like nature books best.
    • Yes: night readers tend to like nature books best more often than day readers.