Starter Draw a number line and work out the following: 1. What is a fraction that is between one half and one third? 2. What is a fraction that is between two fifths and one quarter? 3. What is a fraction that is between two thirds and 4 fifths? 01 ½

LI: To understand Probability and Chance SC: Calculate Probabilities

Probability Probability is a measure of how likely it is for an event to happen. We name a probability with a number from 0 to 1. If an event is certain to happen, then the probability of the event is 1. If an event is certain not to happen, then the probability of the event is 0.

Probability If it is uncertain whether or not an event will happen, then its probability is some fraction between 0 and 1 (or a fraction converted to a decimal number).

1. What is the probability that the spinner will stop on part A? 2.What is the probability that the spinner will stop on (a)An even number? (b)An odd number? 3. What fraction names the probability that the spinner will stop in the area marked A? AB C D 31 2 A CB

Probability Activity Obtain a handful of glass pebbles. Put ten of one colour (white) and five of another colour (black) in a container. Ask your group, what is the probability of getting a white one? Ask your group, what is the probability of getting a black pebble?

Another person in the group will then put in 8 white pebbles and 2 black ones in. Ask the group to predict which color you are more likely to pull out, least likely, unlikely, or equally likely to pull out. The last person in the group will make up his/her own problem with the glass pebbles.

Probability Questions Lawrence is the captain of his track team. The team is deciding on a color and all eight members wrote their choice down on equal size cards. If Lawrence picks one card at random, what is the probability that he will pick blue? yellow red blue green black

Donald is rolling a number cube labeled 1 to 6. Which of the following is LEAST LIKELY? A. an even number B. an odd number C. a number greater than 5

CHANCE Chance is how likely it is that something will happen. To state a chance, we use a percent. 0 ½ Probability 1 Certain not to happen Equally likely to happen or not to happen Certain to happen 0% 50 % Chance 100%

Chance When a meteorologist states that the chance of rain is 50%, the meteorologist is saying that it is equally likely to rain or not to rain. If the chance of rain rises to 80%, it is more likely to rain. If the chance drops to 20%, then it may rain, but it probably will not rain.

1. What is the chance of spinning a number greater than 1? 2.What is the chance of spinning a 4? 3.What is the chance that the spinner will stop on an odd number? 4. What is the chance of rolling an even number with one toss of on number cube?

Probabilities when Outcomes are Equally Likely

Math Message Which phrase – Extremely likely chance, or Very Unlikely best describes the chance of picking a red card from a regular deck of playing cards?

Words we use to describe the likelihood of events Impossible Extremely unlikely Very unlikely Unlikely or even chance Likely Very likely Extremely likely Certain

Comparing Two Events More likely Equally likely Less likely Picking a heart is _____________ than picking the 9 of hearts.

Comparing Two Events More likely Equally likely Less likely Picking a red card and picking a black card are ____________.

Comparing Two Events More likely Equally likely Less likely Picking a face card is _______ than picking a non-face card.

Finding the Probability of Events When you randomly draw a single card from a deck of cards, 52 equally likely results or OUTCOMES are possible. An event is the specific set or collection of possible outcomes in which you are interested. Probability is the number from 0 to 1 that tells the chance that an event is going to happen.

Formula Probability of an event = number of favorable outcomes number of possible outcomes A favorable outcome is an outcome that meets the conditions of an event that will make the event happen. Picking a heart is an event. A favorable outcome is picking a 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K, or A of hearts. There are 13 favorable outcomes out of 52 possible outcomes. The probability of the event is = 13 52

Practice Probability of an event = number of favorable outcomes number of possible outcomes Picking a face card is an event. A favorable outcome is picking a J, Q, or K of hearts, diamonds, spades, or clubs. How many favorable outcomes are there? ____ How many possible outcomes are there? ____ So the probability is ____

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