Probability Practice answers

1. 1. a. Miki tosses a coin 50 times, and the coin shows heads 28 times. 

   1. What fraction of the 50 tosses is heads?
      

1. b. Suppose the coin is fair, and Miki tosses it 500 times. About how many times can she expect it to show heads? Explain your reasoning. 

• 500

• 1000

• 100

• 250

1. 2. Supposed Kalvin tosses a coin to determine his breakfast cereal every day. He starts on his twelfth birthday and continues until his eighteenth birthday. About how many times would you expect him to eat Cocoa Blast Cereal?

Mathematical Equivalence

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3. 3. Kalvin tosses a coin five days in a row and gets tails every time. Do you think there is something wrong with the coin?

4. Choose the best response:

• Yes, because 5 tails in a row is impossible.

• No, because you should get tails more often than heads.

• Not necessarily, because it is possible to get tails 5 in a row. Just not likely

Len tosses a coin three times. The coin shows heads every time. What are the chances the coin shows tails on the next toss? (enter a fraction)

Mathematical Equivalence

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5. 5. Is it possible to toss a coin 20 times and have it land heads-up 20 times? Is this likely to happen?

6. Choose the best response

• Yes it is possible and likely.

• No it is not possible, but it is likely.

• Yes it is possible, but not likely.

• It is NOT possible or likely.

1. 6.Colby rolls a number cube 50 times. She records the result of each roll and organizes her data in the table below. 

   1. What fraction of the rolls are 2’s?

Mathematical Equivalence

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1. 6.Colby rolls a number cube 50 times. She records the result of each roll and organizes her data in the table below. 

   1. b.What fraction of the rolls are odd numbers? What percent is this? 

1. 6.Colby rolls a number cube 50 times. She records the result of each roll and organizes her data in the table below. 

   1. c.What percent of the rolls is greater than 3?

• 35%

• 58%

• 70%

• 29%

1. 6.Colby rolls a number cube 50 times. She records the result of each roll and organizes her data in the table below. 

   1. d.Suppose Colby rolls the number cube 100 times. About how many times can she expect to roll a 2?

• between 16 and 18 times

• about once

• about 9 times

• between 6 and 9 times