Random samples from a known group

Answer Key - Grade 8 Math Worksheet - Building Confidence

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

1. 1.

   5 blue dots and 7 yellow dots. Each sample is drawn without looking; return all counters before the next. Ari has a bag with 5 blue counters out of 12. Ari draws 4 random samples of 6, returning all counters each time. About how many blue draws would match the bag's makeup?

   10

2. Read this first

   Use this

   Each sample is drawn without looking; return all counters before the next.

3. 2.

   Bo has a bag with 3 blue counters out of 10. Bo draws 4 random samples of 5, returning all counters each time. About how many blue draws would match the bag's makeup?

   6
4. 3.

   Jun has a bag with 6 blue counters out of 10. Jun draws 4 random samples of 5, returning all counters each time. About how many blue draws would match the bag's makeup?

   12
5. 4.

   Luz has a bag with 8 blue counters out of 10. Luz draws 4 random samples of 5, returning all counters each time. About how many blue draws would match the bag's makeup?

   16
6. 5.

   7 blue dots and 5 yellow dots. Each sample is drawn without looking; return all counters before the next. Milo has a bag with 7 blue counters out of 12. Milo draws 4 random samples of 6, returning all counters each time. About how many blue draws would match the bag's makeup?

   14
7. 6.

   Each sample is drawn without looking; return all counters before the next. Noah has a bag with 3 blue counters out of 10. Noah draws 6 random samples of 5, returning all counters each time. About how many blue draws would match the bag's makeup?

   9

8. Population dot plot

   5 blue, 5 yellow. Four five-dot sample plots have blue counts 2, 3, 1, 3. Draw without looking and return all counters between samples.

9. 7.

   Ari draws four random samples of five counters from a known bag with 5 blue of 10. Which statement best describes how the samples represent the bag?

   • Only the first sample tells us the bag’s blue share.
   • Different blue counts prove the drawing method was unfair.
   • Equal-size random samples must have the same blue count, as they come from one bag.
   • The samples differ, but their combined blue share is near the bag’s blue share.
10. 8.

    Bo draws four random samples of five counters from a known bag with 4 blue of 10. Which statement best describes how the samples represent the bag?

    • Different blue counts prove the drawing method was unfair.
    • Equal-size random samples must have the same blue count.
    • Only the first sample tells us the bag’s blue share, so the others can be skipped.
    • The samples differ, but their combined blue share is near the bag’s blue share.

11. Population dot plot

    6 blue, 4 yellow. Four five-dot sample plots have blue counts 4, 3, 3, 3. Draw without looking and return all counters between samples.

12. 9.

    Esme draws four random samples of five counters from a known bag with 6 blue of 10. Which statement best describes how the samples represent the bag?

    • Equal-size random samples must have the same blue count.
    • Different blue counts prove the drawing method was unfair, and the samples cannot be trusted.
    • Only the first sample tells us the bag’s blue share.
    • The samples differ, but their combined blue share is near the bag’s blue share.
13. 10.

    Jun draws four random samples of five counters from a known bag with 7 blue of 10. Which statement best describes how the samples represent the bag?

    • Equal-size random samples must have the same blue count.
    • Different blue counts prove the drawing method was unfair.
    • Only the first sample tells us the bag’s blue share.
    • The samples differ, but their combined blue share is near the bag’s blue share.