|Ratios are statements of comparisons of two quantities.
Proportions are equations showing that two ratios are equivalent.
- 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 weather prediction, board games, sports statistics, etc.
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).
To help you understand or learn about finding the probability of two or more events, make a letter cube using one of your number cubes (for example, 1 equals the letter a, 2 equals the letter b, 3 equals the letter c, and so on). Roll one cube and one letter cube.
Probability of two or more events: first find the probability of each event and then multiply the two probabilities to find the probability of both events occurring together.
Example: Rolling a 4 and letter c has a probability of 1/6 (rolling a 4) x 1/6 (rolling a letter c) = 1/36.
The probability would be the same for rolling a 2 and rolling a letter e.
To find the probability of the above two events, multiply 1/36 x 1/36 which equals 1/1296
Directions: Solve the following problems. Show your work on a sheet of paper. Also write at least 5 examples of your own.