probability revision quiz. “i roll a normal dice and get a 7” this event is: impossible a) b) c)...
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“A fair sided dice will land on an odd number” This event is: Impossible a) b) c) d) Unlikely Even Chance Certain L4TRANSCRIPT
Probability Revision Quiz
“I roll a normal dice and get a 7” This event is:
Impossiblea)b)c)d)
Unlikely
Even Chance
Certain L3
“A fair sided dice will land on an odd number” This event is:
Impossiblea)b)c)d)
Unlikely
Even Chance
Certain L4
“It can either rain or not rain. So the probability it rains is ½”. True or False?
True False
L5
I have 10 sweets in a bag. 3 chocolates, 2 toffees and 5 fudges. The probability I pick a
toffee at random is:
510a)
b)
c) d)
210
28
L5
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?
I spin the following spinner
a) What is the probability that the spinner lands on the pink part?
b) What is the probability that the spinner lands on a blue part or a green part?
b) What is the probability that the spinner lands on the red part or the green part or the yellow part or the blue part?
What is PROBABILITY?The chance of some particular thing
happening (EVENT)
Examples
The probability of getting an A in my Math exam
The probability that it rains tomorrow
The probability that I win the lottery today
Possible outcome
s
Two types of Probability
The CALCULATION of something happening
In Theoretical Probability we
PREDICT WHAT SHOULD BE
What ACTUALLY happens
In Experimental Probability we
FIND OUT WHAT IS
THEORETICAL
EXPERIMENTAL
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
• P(Impossible event) =
• P(Certain event) =
• P(any other event) =
• P(event A or event B) =
• The sum of the probabilities of all possible outcomes =
0
1
Between 0 and 1P(event A) + P(event B)
1
The Probability Line
ALWAYS Between 0 and 1 : FRACTION , DECIMAL (or
PERCENTAGE)
Equally Likely
The Probability of an event NOT Happening
• I have a box of 7 different CDs, 3 are music CDs.
What is the probability of NOT picking a music CD?
• In how many ways can I NOT pick a music DVD? 4 ways4/7
Probability of an event NOT happening
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 GENERALThe probability of an event NOT happening is found by
deducting from 1 the probability of that event happening! (finding the COMPLEMENT!)
Probability of an event not happening
Probability of an event NOT happening:
1 – Probability of EVENT happening
Worksheet