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. 2.

   Each sample is drawn without looking; return all counters before the next. 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
3. 3.

   4 blue dots and 6 yellow dots. Each sample is drawn without looking; return all counters before the next. Esme has a bag with 4 blue counters out of 10. Esme draws 5 random samples of 6, returning all counters each time. About how many blue draws would match the bag's makeup?

   12
4. 4.

   7 blue dots and 3 yellow dots. Each sample is drawn without looking; return all counters before the next. Kira has a bag with 7 blue counters out of 10. Kira draws 4 random samples of 5, returning all counters each time. About how many blue draws would match the bag's makeup?

   14
5. 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
6. 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
7. 7.

   Zee has a bag with 8 blue counters out of 10. Zee draws 6 random samples of 5, returning all counters each time. About how many blue draws would match the bag's makeup?

   24

8. Read this first

   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. 8.

   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?

   • The samples differ, but their combined blue share is near the bag’s blue share.
   • Different blue counts prove the drawing method was unfair.
   • Only the first sample tells us the bag’s blue share.
   • Equal-size random samples must have the same blue count, as they come from one bag.
10. 9.

    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?

    • Only the first sample tells us the bag’s blue share, so the others can be skipped.
    • Equal-size random samples must have the same blue count.
    • Different blue counts prove the drawing method was unfair.
    • 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. 10.

    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?

    • The samples differ, but their combined blue share is near the bag’s blue share.
    • Only the first sample tells us the bag’s blue share.
    • 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.