 Probability is the likelihood or chance of an event occurring  Probability can be calculated by: Favourable outcomes Possible outcomes Probabilities can be expressed as percents, ratios or fractions

 A spinner is divided into 5 equal sections. The spinner is spun once. Find the following probabilities. Write each as a fraction, ratio and percent.  a) prob. of orange  b) prob. of green and yellow

 a) There are five possible outcomes: red, orange, green, yellow and purple  There is only one favourable outcome - orange P(orange) = favourable outcomes/possible out. P(orange) = 1/5 = 1:5 = 20%

 b) There are five possible outcomes: red, orange, green, yellow and purple There are two favourable outcomes – green and yellow P(grn + yel) = favourable outcomes/possible out. P(grn + yel) = 2/5 = 2:5 = 40%

 Independent events = the outcome of one event has no affect on the outcome of another event  Example: if you rolled a dice you might end up with a 4. If you rolled the dice again, the first 4 would not affect the next roll. You could roll any of the six possible numbers.

 Dependent events = the outcome of one event affects the outcome of a second event. Example: If you drew a card from a deck you would have a 1/52 chance of choosing that card. If you did NOT replace that card and drew another, the chance of getting any one card would now be 1/51. Sample Space = all possible outcomes of an experiment

 Grade 7 textbook  Page 163 # 3,4,5,6,7,8,9