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

   	Pizza	Salad	Soup	Total
   Early lunch	5	16	7	28
   Late lunch	23	11	19	53
   Total	28	27	26	81

2. 1.

   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

3. 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

4. 2.

   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
5. 3.

   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

6. Two-way table of singers and players

   	Summer	Fall	Winter	Total
   Band	11	6	21	38
   Choir	5	4	23	32
   Total	16	10	44	70

7. 4.

   Luz sorted singers and players in a two-way table. Of the singers and players in the "Winter" column, what percent are in choir, to the nearest whole percent?

   52

8. 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

9. 5.

   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
10. 6.

    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
11. 7.

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

    • Yes: 9th graders tend to walk to school more often than 10th graders.
    • Yes: 10th graders tend to walk to school more often than 9th graders.
    • Yes: being in 9th grade makes students walk to school.
    • No: about the same share of each group tends to walk to school.
    • Yes: more 10th graders walk to school, 36 against 22.
12. 8.

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

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

13. Two-way table of club members

    	Zoo	Museum	Aquarium	Total
    Science club	37	23	14	74
    Art club	14	11	13	38
    Total	51	34	27	112

14. 9.

    Tala's two-way table counts club members. Is there a link between the club and whether club members vote for the museum?

    • Yes: being in the science club makes club members vote for the museum.
    • Yes: more science club members vote for the museum, 23 against 11.
    • No: about the same share of each group tends to vote for the museum.
    • Yes: science club members tend to vote for the museum more often than art club members.
15. 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?

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