Probability Revision Quiz I roll a normal dice

Probability Revision Quiz

“I roll a normal dice and get a 7” This event is: a) Impossible b) Unlikely c) Even Chance d) Certain L 3

“A fair sided dice will land on an odd number” This event is: a) Impossible b) Unlikely c) Even Chance d) Certain L 4

Put the following events in order of probability, from least likely to most likely 1. 2. 3. 4. 5. Getting a head on the toss of a coin Getting a 6 on the roll of a dice Getting the Ace of Hearts from a deck of cards Tomorrow being Christmas Day The day tomorrow ending with a Y

“It can either rain or not rain. So the probability it rains is ½”. True or False? True False L 5

“I roll a dice and get a number less than 7” Where should this event go on the probability line? A 0 B C D E F 0. 5 1 L 5

“I roll a dice and get a 1, 2 or 3” Where should this event go on the probability line? A 0 B C D E F 0. 5 1 L 5

“I roll a dice and get a 5” Where should this event go on the probability line? A 0 B C D E F 0. 5 1 L 5

I have 10 sweets in a bag. 3 chocolates, 2 toffees and 5 fudges. The probability I pick a toffee at random is: a) c) b) d) L 5

The letters from the word NECCESSITY are put on cards and turned over. I pick one at random. What is the probability that I pick a vowel?

“If you flip a fair coin 100 times, you will get 50 ‘tails’”. True or False? True False L 5

a) c) b) d) L 6

The probability a traffic light is red is 0. 3, the probability it is green is 0. 65. What is the probability it is amber? a) b) c) d) L 6

A bag contains 3 red, 5 yellow, 2 blue and 6 green cubes. A cube is picked at random. What is the probability a blue or yellow cube is not picked? a) c) b) d) L 6

a) c) b) d) L 6

Bill rolls a dice 20 times and gets 9 sixes. Do you think the dice is biased? Yes No L 7

What is The chance of some particular PROBABILITY? thing happening (EVENT) Examples Possible outcomes The probability of getting an A in my Math exam The probability that it rains tomorrow The probability that I win the lottery today

Two types of EXPERIMENTA Probability THEORETICAL The CALCULATION of something happening In Theoretical Probability we PREDICT WHAT SHOULD BE L What ACTUALLY happens In Experimental Probability we FIND OUT WHAT IS Why can the results of experimental probability be different to theoretical probability calculations? No one can tell exactly what is going to happen in the future, what happened in the past can help predict the future which is what we do in theoretical probability BUT we can never know for sure what actually happens which is what we find out in experimental probability

P(EVENT) P(Event A) = The number of ways A can happen The total number of possible ways 0 P(Impossible event) = 1 P(Certain event) = P(any other event) = P(event A or event B) = Between 0 and 1 P(event A) + P(event B)

The Probability Line Equally Likely Probability of an event ALWAYS Between 0 and 1 Calculated as a fractions in their lowest terms – can be written as decimals or percentages

Impossible, Unlikely, Equally Likely, Likely or Certain?

52 cards in all

Probability of an event NOT happening I have a box of 7 different DVDs, 3 are music DVDs. What is the probability of NOT picking a music DVD? In how many ways can I NOT pick a music DVD? 4 ways

Probability of an event NOT happening So P(NOT Music CD) = 4/7 Question: What is the relationship between P(Music CD) = 3/7 and P(NOT Music CD) = 4/7 P(NOT Music CD) = 7/7 – 3/7 = 4/7 = 1 – P(Music CD) IN GENERAL The probability of an event NOT happening is found by deducting from 1 the probability of the event happening! (COMPLEMENT!)

Probability of an event NOT happening P(NOT EVENT)= 1 – P(EVENT)