7.3 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 ____

Brainpop BrainPOP | Basic Probability

Problems 1 and 2 on MJ p. 192

Partner work MJ page 192