Basic Probability
Biased/ Unbiased
Reading Tables
Worded questions
Random Probability Questions
100
What fraction is equal to a probability of 25%?
1/4
100
Biased (Yes) or Unbiased (No)?
Eight citizens are asked their opinions about what trash should be collected.
Yes, Biased, sample size too small
100
In an experiment, a standard six-sided die was rolled 72 times. The results are shown in the table.
Which number on the die was obtained the expected number of times?
1/6 x 72 OR 72 divided by 6
= 12
100
A cafe menu has 3 entrees, 5 main courses and 2 desserts. Ariana is choosing a three-course meal consisting of an entree, a main course and a dessert.
How many different three-course meals can Ariana choose?
3 x 5 x 2 = 30
100
The probability of winning a game is .
Which expression represents the probability of winning two consecutive games?
a) 7/10 x 6/9
b) 7/10 x 6/10
c) 7/10 x 7/9
d) 7/10 x 7/10
D = 7/10 x 7/10
200
A newspaper states it will 'most probably rain tomorrow'.
What best fits that the probability will most likely occur?
80%
200
Biased? or Unbiased?
A phone-in survey is taken by a radio station to see how many listeners enjoy jazz in the morning.
Yes, Biased, response are only from listeners who decide to call in
200
The diagram shows a spinner.
The arrow is spun and will stop in one of the six sections.
What is the probability that the arrow will stop in a section containing a number greater
than 4?
1/2
200
In a survey of 200 randomly selected Year 12 students it was found that 180 use social media.
Based on this survey, approximately how many of 75 000 Year 12 students would be expected to use social media?
180/200 = 90%
0.9 x 75000 = 67500
200
ach time she throws a dart, the probability that Mary hits the dartboard is 2/7.
She throws two darts, one after the other.
What is the probability that she hits the dartboard with both darts
a) 1/21
b) 4/49
c) 2/7
d) 4/7
2/7 x 2/7 = 4/49
300
The probability of an event occurring is 9/10.
Which statement best fits the probability of this event occurring?
a) Likely
b) Certain
c) Unlikely
d) Even chance
Highly likely - not certain
300
Biased? or Unbiased?
Every fortieth student who enters the school is asked to name their favorite sport.
Unbiased. Its systematic.
300
Four radio stations reported the probability of rain as shown in the table.
Which radio station reported the highest probability of rain?
Change all to decimals - 2DL
300
An experiment has three distinct outcomes, A, B and C.
Outcome A occurs 50% of the time. Outcome B occurs 23% of the time.
What is the expected number of times outcome C would occur if the experiment is conducted 500 times?
100 - 50 - 23 = 27
0.27 x 500 = 135
300
Kay randomly selected a marble from a bag of marbles, recorded its colour and returned it to the bag. She repeated this process a number of times.
Based on these results, what is the best estimate of the probability that Kay will choose a green marble on her next selection?
a) 5/24
b) 1/24
c) 1/6
d) 1/5
c) 1/6
400
What fraction is equal to a probability of 20%?
1/5
400
Biased? Or Unbiased?
Each math class randomly selects two students do represent their class on an advisory panel being assembled by the principal.
Unbiased. At random
400
A group of 150 people was surveyed and the results recorded.
A person is selected at random from the surveyed group.
What is the probability that the person selected is a male who does not own a mobile?
28/150
400
Which of the following events would be LEAST likely to occur?
a) Tossing a fair coin and obtaining a head
b) Rolling a standard six-sided die and obtaining a 3
c) Randomly selecting the letter 'G' from the 26 letters of the alphabet
d) Winning first prize in a raffle of 100 tickets in which you have 4 tickets
c) 1/26
400
Leanne copied a two-way table into her book.
Leanne made an error in copying one of the values in the shaded section of the table.
Which value has been incorrectly copied?
a) The number of males in full-time work
b) The number of males in part-time work
c) The number of females in full-time work
d) The number of females in part-time work
D
500
The letter A, B and C are used to make a three letter company name.
How many different company manes can be made?
3 x 2 x 1 = 6
500
An unbiased coin is tossed 10 times.
A tail is obtained on each of the first 9 tosses.
What is the probability that a tail is obtained on the 10th toss.
1/2 even chance
500
Some men and women were surveyed at a football game. They were asked which team they supported. The results are shown in the two-way table.
What percentage of the women surveyed supported Team B, correct to the nearest percent?
90/165 = 0.5454...
500
Jaz has 2 bags of apples.
Bag A contains 4 red apples and 3 green apples.
Bag B contains 3 red apples and 1 green apple.
Jaz chooses an apple from one of the bags.
Which tree diagram could be used to determine the probability that Jaz chooses a red apple?
A
500
What fraction is equal to a probability of 76%?
19/25