7th Grade Math

Test PracticeT

462 Probability and Predictions

7. CHALLENGE The experimental probability of a coin landing on heads
   is _ 127. If the coin landed on tails 30 times, find the number of tosses.


8. REASONING Twenty sharpened pencils are placed in a box containing
   an unknown number of unsharpened pencils. Suppose 15 pencils are
   taken out at random, of which five are sharpened. Based on this, is it
   reasonable to assume that the number of unsharpened pencils was 40?
   Explain your reasoning.


9. E WRITE MATH Compare and contrast experimental probability and
   theoretical probability.

C

Eight cards numbered 1–8 are shuffled together. A card is drawn at random.

It is not replaced. Find each probability. (Lesson 2B)

12. P(8 then 4) 13. P(even then odd)


13. PUMPKINS The table shows the number of participants at

Competition

Perfect

Pumpkin

Biggest

Pumpkin

18

12

Number of

Participants

Prize1st

the pumpkin festival. A ribbon will be awarded to the top

three participants in the perfect pumpkin contest. Find the

number of ways the ribbons can be awarded in the perfect

pumpkin contest. (Lesson 1D)

15. What is the probability of rolling a number greater than 4
    on a number cube? (Lesson 1A)


16. The table shows Mitch’s record for the
    last thirty par-3 holes he has played.

Mitch’s Golf Results

Score Number of Holes

2 4

314

4 9

5 3

Based on this record, what is the

probability that Mitch will score a

2 or 3 on the next par-3 hole?

A. _^79 C. _ 103

B. ^35 D. 509

11. J.R. tossed a coin 100 times.

Number of Tosses 0

Tossing a Coin

20

40

60

80

Heads Tails

Based on his results, what is the

experimental probability of tossing

tails on the next toss?

F. _^15 H. _^35

G. ^23 I. ^45

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