D1 Probability of One Event

Transcription

1 D Probability of One Event Year 3/4. I have 3 bags of marbles. Bag A contains 0 marbles, Bag B contains 20 marbles and Bag C contains 30 marbles. One marble in each bag is red. a) Join up each statement to the correct label. i) If I take out marble from Bag A with my eyes shut, it will be red. ii) iii) If I take out 20 marbles from Bag B with my eyes shut, none will be red. If I take out 2 marbles from each bag with my eyes shut, one will be blue. Certain Possible but not certain Impossible b) Which bag gives me the best chance of picking the red marble? Mr. Silly does not know his compass directions. He paints the letters N, E, S and W on the compass at random. What chance does he have of painting the compass correctly? W N E S 3. Predict the results for each outcome first, then do the experiment. Throw a dice 20 times and keep a tally of how it lands in this table. Prediction Tally of 20 throws Totals How many times did you get: a) a 2 or a b) less than c) not less than d) not more than e) more than 6?.....

2 D Probability of One Event, Year 3/4 4. Three boys, A, B and C, decided to have a race. We know that there was a tie but not for which place. a) What could the finishing order be? Show all the possibilities. st 2nd/3rd b) If each possible result has an equal chance of happening, what is the chance that there was a tie for st place? At the entrance to a wood there are 5 paths leading to the first clearing. From the first clearing there are 6 paths leading to the 2nd clearing. From the 2nd clearing there are 3 paths leading to the 3rd clearing. a) Draw a diagram to show. b) How many routes could you take from the st clearing to the 3rd clearing? c) What chance would you have of guessing correctly a person's route from the entrance of the wood to the 3rd clearing? 2

3 D Probability of One Event Year 5/6. How certain are you of these outcomes occurring? Write C for certain, P for possible but not certain or I for impossible. a) The next Olympic Games will be in the year b) The next time I throw a dice I will get a 5. c) The next time I throw a dice I will get a 0. d) Next year, the number of boys born will be twice the number of girls. e) Next year, fewer boys than girls will be born. 2. In a bag there are 50 marbles altogether. The marbles are either black or white. The ratio of black marbles to white marbles is : 4. a) How many marbles are there of each colour? black b) If you take a marble out of the bag with your eyes shut, what is the probability that it will be white? white 3. Seven children draw lots in the hope of winning a prize. If each child has an equal chance of winning, what is the probability of each of these outcomes happening? Join the outcomes to the matching points on the probability scale. a) C wins. b) A or D wins. c) G or E or C or A wins. d) B and F win. e) G does not win. f) Neither D nor E wins

4 D Probability of One Event, Year 5/6 4. A marble is dropped into this maze and has an equal chance of falling to the left or to the right. a) In how many ways can the marble come out at: A B C D E F? b) How many routes are there altogether? c) What is the probability of each outcome? Outcome A B C D E F A B C D E F Probability 5. A dice is thrown 00 times and a tally is kept of the numbers thrown. The table shows the number of times (frequency) that each number (outcome) is thrown. Outcome Frequency Relative frequency a) Fill in the bottom row of the table to show the relative frequency. b) Do you think that the dice is biased or unbiased? Give a reason for your answer

5 D Probability of One Event, Year 5/6 6. This probability scale shows the probabilities of 6 outcomes: A, B, C, D, E and F. A C E F B D a) Which outcome is: i) certain to happen ii) impossible iii) the most unlikely to happen but is not impossible? b) Which outcomes are more likely than C to happen? c) Which outcome is the least likely to happen, but is not impossible? 7. A bag contains 2 red, 3 yellow and 5 green marbles. If you took out a marble with your eyes closed, what chance would you give to each of these outcomes? Join each outcome to the appropriate level of chance. a) The marble taken out is green. b) The marble taken out is red. c) The marble taken out is either red or yellow. d) The marble taken out is not yellow. e) The marble taken out is black. f) The marble taken out is not black. Certain Likely Equally likely as unlikely Unlikely Impossible 5