Common Core: 7th Grade Math : Finding Theoretical Probability

Study concepts, example questions & explanations for Common Core: 7th Grade Math

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Example Questions

Example Question #991 : Grade 7

Kelly spun a spinner, which is pictured below, \(\displaystyle 35\) times. She recorded her results in the table provided. What is the theoretical probability of the spinner landing on the orange section? 


1Screen shot 2016 03 03 at 9.49.24 am

Possible Answers:

\(\displaystyle \frac{2}{3}\)

\(\displaystyle 2\)

\(\displaystyle 1\)

\(\displaystyle \frac{1}{6}\)

\(\displaystyle \frac{1}{3}\)

Correct answer:

\(\displaystyle \frac{1}{3}\)

Explanation:

The theoretical probability is what should happen. In this case, we have \(\displaystyle 6\) spaces and \(\displaystyle 2\) of those spaces is orange; thus, the theoretical probability of the spinner landing on orange should always be \(\displaystyle \frac{2}{6}\) or \(\displaystyle \frac{1}{3}\)

Example Question #992 : Grade 7

Kelly spun a spinner, which is pictured below, \(\displaystyle 40\) times. She recorded her results in the table provided. What is the theoretical probability of the spinner landing on the yellow section? 

1Screen shot 2016 03 03 at 10.09.46 am

Possible Answers:

\(\displaystyle 3\)

\(\displaystyle 6\)

\(\displaystyle 1\)

\(\displaystyle \frac{1}{6}\)

\(\displaystyle \frac{1}{2}\)

Correct answer:

\(\displaystyle \frac{1}{2}\)

Explanation:

The theoretical probability is what should happen. In this case, we have \(\displaystyle 6\) spaces and \(\displaystyle 3\) of those spaces is yellow; thus, the theoretical probability of the spinner landing on yellow should always be \(\displaystyle \frac{3}{6}\) or \(\displaystyle \frac{1}{2}\)

Example Question #993 : Grade 7

Kelly spun a spinner, which is pictured below, \(\displaystyle 40\) times. She recorded her results in the table provided. What is the theoretical probability of the spinner landing on the green section? 

1Screen shot 2016 03 03 at 10.09.46 am

Possible Answers:

\(\displaystyle 6\)

\(\displaystyle \frac{1}{6}\)

\(\displaystyle \frac{1}{2}\)

\(\displaystyle \frac{2}{6}\)

\(\displaystyle 9\)

Correct answer:

\(\displaystyle \frac{1}{6}\)

Explanation:

The theoretical probability is what should happen. In this case, we have \(\displaystyle 6\) spaces and \(\displaystyle 1\) of those spaces is green; thus, the theoretical probability of the spinner landing on green should always be \(\displaystyle \frac{1}{6}\) 

Example Question #994 : Grade 7

Kelly spun a spinner, which is pictured below, \(\displaystyle 50\) times. She recorded her results in the table provided. Is the experimental probability of landing on pink more likely, less likely, or equally likely in comparison to the theoretical probability? 

1Screen shot 2016 03 03 at 9.14.25 am

 

Possible Answers:

Less likely 

Results can't be found based on the data provided 

More likely 

Equally likely 

Correct answer:

More likely 

Explanation:

The theoretical probability is what should happen. In this case, we have \(\displaystyle 6\) spaces and \(\displaystyle 1\) of those spaces is pink; thus, the theoretical probability of the spinner landing on pink should always be \(\displaystyle \frac{1}{6}\)

The experimental probability is what actually happened in an experiment. In this case, Kelly spun the spinner \(\displaystyle 50\) times, and she landed on pink \(\displaystyle \frac{13}{50}\) times; thus, our experimental probability is \(\displaystyle \frac{13}{50}\)

In order to compare the theoretical probability and the experimental probability let's convert the fractions into decimals so we can put them on a number line:

\(\displaystyle \frac{1}{6}=0.17\)

\(\displaystyle \frac{13}{50}=0.26\)

2

A probability closer to \(\displaystyle 1\) means that an event is more likely to occur. In this case, \(\displaystyle 0.26\) is closer to \(\displaystyle 1\); thus, the experimental probability is more likely than the theoretical probability. 

Example Question #1 : Finding Theoretical Probability

Kelly spun a spinner, which is pictured below, \(\displaystyle 35\) times. She recorded her results in the table provided. Is the experimental probability of landing on orange more likely, less likely, or equally likely in comparison to the theoretical probability? 

1Screen shot 2016 03 03 at 9.49.24 am

Possible Answers:

Results can't be found based on the data provided 

Less likely 

Equally likely 

More likely 

Correct answer:

More likely 

Explanation:

The theoretical probability is what should happen. In this case, we have \(\displaystyle 6\) spaces and \(\displaystyle 2\) of those spaces is orange; thus, the theoretical probability of the spinner landing on orange should always be \(\displaystyle \frac{2}{6}\) or \(\displaystyle \frac{1}{3}\)

The experimental probability is what actually happened in an experiment. In this case, Kelly spun the spinner \(\displaystyle 35\) times, and she landed on orange \(\displaystyle \frac{13}{35}\) times; thus, our experimental probability is \(\displaystyle \frac{13}{35}\)

In order to compare the theoretical probability and the experimental probability let's convert the fractions into decimals so we can put them on a number line:

\(\displaystyle \frac{1}{3}=0.33\)

\(\displaystyle \frac{13}{35}=0.37\)

2

A probability closer to \(\displaystyle 1\) means that an event is more likely to occur. In this case, \(\displaystyle 0.37\) is closer to \(\displaystyle 1\); thus, the experimental probability is more likely than the theoretical probability. 

Example Question #1 : Finding Theoretical Probability

Kelly spun a spinner, which is pictured below, \(\displaystyle 50\) times. The spinner had six equally-sized sections, each of a different color, and she recorded her results in the table provided. What is the theoretical probability of the spinner landing on the pink section? 

1Screen shot 2016 03 03 at 9.14.25 am

Possible Answers:

\(\displaystyle \frac{13}{50}\)

\(\displaystyle 13\)

\(\displaystyle \frac{1}{6}\)

\(\displaystyle 12\)

\(\displaystyle \frac{12}{50}\)

Correct answer:

\(\displaystyle \frac{1}{6}\)

Explanation:

The theoretical probability is what should happen. In this case, we have \(\displaystyle 6\) spaces and \(\displaystyle 1\) of those spaces is pink; thus, the theoretical probability of the spinner landing on pink should always be \(\displaystyle \frac{1}{6}\)

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