Probability
- Is the chance of an event happening.
- If a particular outcome can never occur, its probability is 0.
- If an outcome is certain to occur, its probability is 1.
- In general, if p is the probability that a specific outcome will occur, values of p fall in the range 0 <= p <= 1.
- Probability may be expressed as either a decimal, a fraction, or a ratio.
- Probability examples in everyday life include physical sciences, commerce, weather forecasting, board games, sports statistics, etc.
Examples:
What are the chances that the sun will shine this month? (likely)
What are the chances that you, a 11 year old boy, will be driving a car today? (unlikely)
What are the chances of tossing heads or tails on a coin? (equally likely)
Coin: 2 sides
The probability of rolling heads is 1/2
The probability of rolling tails is 1/2
Cube: 6 sides
Take a number cube and label the sides 1 - 6.
The probability of rolling a 3 is one outcome out of a total of six possible outcomes, that is 1/6.
Similarly, the probability of rolling a 5 is also 1/6.
The probability of rolling an odd number (1, 3, 5) = three outcomes out of a total of six possible outcomes = 3/6 = 1/2
Probability of rolling an even number is also same as rolling an odd numbers (3/6 or 1/2).
Example: A bag contains 4 red balls and 3 green balls. What is the probability of picking a green ball?
Since there are three green and 1 is picked out at a time, the probability is 3/7.
Answer: 3/7
Directions: Solve the following questions. Also write at least 10 examples of your own.
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