UA · Unit 7 review

1. 1.

   Shoe size vs. quiz score for a class looks like a cloud with no trend. Association?

   Answer. none

   none

2. 2.

   A trend line is y = 3x + 4. Predict y when x = 9.

   Answer. 31

   y = 3(9) + 4 = 31.

3. 3.

   A table shows how 6th graders get to school: walk 13, bike 14, bus 12. How many students were surveyed?

   Walk	Bike	Bus
   13	14	12

   Answer. 39

   13 + 14 + 12 = 39.

4. 4.

   A two-way table records whether students play a sport (rows: Grade 7, Grade 8; columns: Yes, No). Grade 7: 11 yes, 6 no. Grade 8: 12 yes, 14 no. What fraction of all students play a sport?

   Yes	No
   G7 11	6
   G8 12	14

   Answer. 2343

   Yes total 23 out of 43 = 2343.

5. 5.

   As outdoor temperature rises, hot-cocoa sales fall. Association? Write a complete answer — Owen will compare with a partner.

   Answer. negative

   negative

6. 6.

   A trend line is y = 3x + 9. Predict y when x = 6. Then Jonah needs 3 of that amount. What is the total they need?

   Answer. 81

   y = 3(6) + 9 = 27. Then multiply by 3: 81.

7. 7.

   A table shows how 6th graders get to school: walk 15, bike 14, bus 19. How many students were surveyed? Then Priya needs 3 of that amount. What is the total they need?

   Walk	Bike	Bus
   15	14	19

   Answer. 144

   15 + 14 + 19 = 48. Then multiply by 3: 144.

8. 8.

   A two-way table records whether students play a sport (rows: Grade 7, Grade 8; columns: Yes, No). Grade 7: 13 yes, 9 no. Grade 8: 6 yes, 11 no. What fraction of all students play a sport? Then Owen needs 3 of that amount. What is the total they need?

   Yes	No
   G7 13	9
   G8 6	11

   Answer. 1613

   Yes total 19 out of 39 = 1939. Then multiply by 3: 1613.

9. 9.

   As hours studied increase, test scores tend to increase. What kind of association? Write a complete answer — Sam will compare with a partner.

   Answer. positive

   positive

10. 10.

    A trend line is y = 6x + 4. Predict y when x = 10. Then Malik needs 4 of that amount. What is the total they need?

    Answer. 256

    y = 6(10) + 4 = 64. Then multiply by 4: 256.

11. 11.

    Think

    Ava tried this problem:
    A table shows how 6th graders get to school: walk 15, bike 11, bus 13. How many students were surveyed?
    Ava wrote 38. That is not correct. What is the right answer?

    Walk	Bike	Bus
    15	11	13

    Answer. 39

    Ava’s answer 38 is off. 15 + 11 + 13 = 39.

12. 12.

    Think

    Owen tried this problem:
    A two-way table records whether students play a sport (rows: Grade 7, Grade 8; columns: Yes, No). Grade 7: 13 yes, 11 no. Grade 8: 10 yes, 12 no. What fraction of all students play a sport?
    Owen wrote 13. That is not correct. What is the right answer?

    Yes	No
    G7 13	11
    G8 10	12

    Answer. 12

    Owen’s answer 13 is off. Yes total 23 out of 46 = 12.

Original extra practice. Keys are computed from the items, not guessed.