MIA · Mixed set · Unit 5

1. 1.

   Priya leaves a 40% tip on a $200 bill. How much is the tip?

   Answer. $80

   40% of 200 = 80.

2. 2.

   A price goes from $120 to $144. What is the percent increase?

   Answer. 20%

   Change = 24; divide by 120 → 20%.

3. 3.

   Is this sampling method random? The school emails a survey to every 10th student on the roster.

   Answer. random (systematic from a list)

   random (systematic from a list)

4. 4.

   A population mean is unknown. Sample means from samples of size 100 tend to vary. Which sample size would you expect to give a sample mean closer to the population mean: 10 or 100?

   Answer. 100

   Larger random samples tend to have sample means closer to the population mean.

5. 5.

   Class A has median 19 and IQR 4. Class B has median 25 and IQR 4. Which class typically scored higher? Write a complete answer — Owen will compare with a partner.

   Answer. Class B

   Same spread (IQR 4), higher median in Class B (25 vs 19).

6. 6.

   Sam leaves a 20% tip on a $160 bill. How much is the tip? Then Owen needs 4 of that amount. What is the total they need?

   Answer. $128

   20% of 160 = 32. Then multiply by 4: $128.

7. 7.

   A price goes from $50 to $37.5. What is the percent decrease? Write a complete answer — Jonah will compare with a partner.

   Answer. 25%

   Change = 12.5; divide by 50 → 25%.

8. 8.

   Is this sampling method random? A reporter asks only the first 8 fans at the front of a line. Write a complete answer — Grace will compare with a partner.

   Answer. not random (convenience)

   not random (convenience)

9. 9.

   A population mean is unknown. Sample means from samples of size 100 tend to vary. Which sample size would you expect to give a sample mean closer to the population mean: 10 or 100? Then Luis needs 2 of that amount. What is the total they need?

   Answer. 200

   Larger random samples tend to have sample means closer to the population mean. Then multiply by 2: 200.

10. 10.

    Class A has median 16 and IQR 4. Class B has median 22 and IQR 4. Which class typically scored higher? Write a complete answer — Theo will compare with a partner.

    Answer. Class B

    Same spread (IQR 4), higher median in Class B (22 vs 16).

11. 11.

    Think

    Elena tried this problem:
    Ava leaves a 30% tip on a $160 bill. How much is the tip?
    Elena wrote $47. That is not correct. What is the right answer?

    Answer. $48

    Elena’s answer $47 is off. 30% of 160 = 48.

12. 12.

    Think

    Nora tried this problem:
    A price goes from $80 to $96. What is the percent increase?
    Nora wrote 40%. That is not correct. What is the right answer?

    Answer. 20%

    Nora’s answer 40% is off. Change = 16; divide by 80 → 20%.

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