Probability Language
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Either paper 1 mark
A fair six-sided dice is rolled.
Choose the word from this list that best describes the probability that the score is less than 7.
impossible, unlikely, even chance, likely, certain
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Either paper 1 mark
A bag contains 30 counters. 15 of the counters are blue.
One counter is taken from the bag at random.
Which point on the probability scale, A, B or C, shows the probability that the counter is blue?
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Either paper 2 marks
The probability that a light bulb made at a factory lasts more than 1000 hours is shown by the point marked A on the probability scale.
(a)Write down this probability as a decimal.
(b)Choose the word that best describes this probability: unlikely, even chance or likely.
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Either paper 3 marks
A bag holds \(14\) counters. Each counter is pink, grey or brown.
\(8\) of the counters are pink, \(1\) are grey and \(5\) are brown.
One counter is taken from the bag at random.
(a)Write down the colour the counter is most likely to be.
(b)Write down the colour the counter is least likely to be.
(c)Choose the word from this list that best describes the probability that the counter is pink.
unlikely, even chance, likely
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Either paper 3 marks
A bag contains 9 counters that are purple and 3 counters that are orange.
One counter is taken at random.
Idris says the probability that it is purple is \(\frac{ 9 }{ 3 }\).
(a)Explain how you can tell that Idris must be wrong, without working the probability out.
(b)Work out the correct probability, giving your answer as a fraction in its simplest form.
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Either paper 4 marks
A fair spinner has five sections, labelled A to E. The spinner is spun once.
(a)Complete these statements.
The spinner is most likely to land on section ________
The spinner is equally likely to land on sections ________ and ________
(b)Two different spinners are spun. One spinner has sections labelled with letters. The other spinner has sections labelled with numbers.
Here is a list of all the possible outcomes.
P 1, P 2, P 3, Q 1, Q 2, Q 3, R 1, R 2, R 3, S 1, S 2, S 3
Show the possible sections on the two spinners.
Letter spinner: ________
Number spinner: ________
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Either paper 2 marks
A fair ordinary dice is rolled once.
(a)On the probability scale, mark with a cross the probability that the dice lands on a number less than 6.
(b)On the probability scale, mark with a cross the probability that the dice lands on a number greater than 4.
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Either paper 2 marks
The table gives the probability of each of four events.
Event A B C D Probability \(0.6\) \(40\%\) \(\frac{1}{20}\) \(0.15\) Write the four events in order of likelihood, starting with the least likely.
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Either paper 2 marks(a)
The probability that a machine breaks down in a day is \(0.5\).
Calculate the probability that the machine does not break down.
(b)Describe in words how likely it is that the machine does not break down.
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Either paper 2 marks
The first bag contains 12 counters. 3 of them are orange.
The second bag contains 18 counters. 6 of them are orange.
One counter is taken at random from each bag.
Which bag gives the better chance of taking a counter that is orange?
You must show your working.
- certain
- C
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(a) \(0.5\)
(b) even chance -
(a) Pink
(b) Grey
(c) likely -
(a) \(\frac{ 9 }{ 3 }\) is bigger than 1, and no probability can be more than 1.
(b) \(\frac{ 3 }{ 4 }\) -
(a) Most likely: section D. Equally likely: sections A and B.
(b) Letter spinner: P, Q, R, S. Number spinner: 1, 2, 3. -
(a) \(\frac{ 5 }{ 6 }\): a cross on the tick 5 divisions along from the 0 end
(b) \(\frac{ 1 }{ 3 }\): a cross on the tick 2 divisions along from the 0 end(a)(b) - C, D, B, A
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(a) \(0.5\)
(b) an even chance - the second bag, because \(\frac{ 12 }{36}\) is bigger than \(\frac{ 9 }{36}\)
Takes a couple of seconds the first time a sheet is made.