Jasmine throws two ordinary fair 6-sided dice at the same time and notes the numbers on the uppermost faces. The events A and B are defined as follows.
A: The sum of the two numbers is less than 6.
B: The difference between the two numbers is at most 2.
Determine whether or not the events A and B are independent.
A fair six-sided die is thrown twice and the scores are noted. Event X is defined as ‘The total of the two scores is 4’. Event Y is defined as ‘The first score is 2 or 5’. Are events X and Y independent? Justify your answer.
In a group of students, the numbers of boys and girls studying Art, Music and Drama are given in the following table. Each of these 160 students is studying exactly one of these subjects.
| Art | Music | Drama | |
|---|---|---|---|
| Boys | 24 | 40 | 32 |
| Girls | 15 | 12 | 37 |
In a group of students, \(\frac{3}{4}\) are male. The proportion of male students who like their curry hot is \(\frac{3}{5}\) and the proportion of female students who like their curry hot is \(\frac{4}{5}\). One student is chosen at random.
Last Saturday, Sarah recorded the colour and type of 160 cars in a car park. All the cars that were not red or silver in colour were grouped together as 'other'. Her results are shown in the following table.
| Colour of car | Saloon | Hatchback | Estate |
|---|---|---|---|
| Red | 20 | 40 | 12 |
| Silver | 14 | 26 | 10 |
| Other | 6 | 24 | 8 |
Ashfaq throws two fair dice and notes the numbers obtained. R is the event 'The product of the two numbers is 12'. T is the event 'One of the numbers is odd and one of the numbers is even'. By finding appropriate probabilities, determine whether events R and T are independent.
For a group of 250 cars the numbers, classified by colour and country of manufacture, are shown in the table.
| Germany | Japan | Korea | |
|---|---|---|---|
| Silver | 40 | 26 | 34 |
| White | 32 | 22 | 26 |
| Red | 28 | 12 | 30 |
One car is selected at random from this group. Find the probability that the selected car is
X is the event that the selected car is white. Y is the event that the selected car is manufactured in Germany.
(iii) By using appropriate probabilities, determine whether events X and Y are independent.
In a group of 30 adults, 25 are right-handed and 8 wear spectacles. The number who are right-handed and do not wear spectacles is 19.
(i) Copy and complete the following table to show the number of adults in each category.
| Wears spectacles | Does not wear spectacles | Total | |
|---|---|---|---|
| Right-handed | |||
| Not right-handed | |||
| Total | 30 |
An adult is chosen at random from the group. Event X is ‘the adult chosen is right-handed’; event Y is ‘the adult chosen wears spectacles’.
(ii) Determine whether X and Y are independent events, justifying your answer.
A fair eight-sided die has faces marked 1, 2, 3, 4, 5, 6, 7, 8. The score when the die is thrown is the number on the face the die lands on. The die is thrown twice.
Ellie throws two fair tetrahedral dice, each with faces numbered 1, 2, 3, and 4. She notes the numbers on the faces that the dice land on. Event S is 'the sum of the two numbers is 4'. Event T is 'the product of the two numbers is an odd number'.
Jason throws two fair dice, each with faces numbered 1 to 6. Event A is ‘one of the numbers obtained is divisible by 3 and the other number is not divisible by 3’. Event B is ‘the product of the two numbers obtained is even’.
Marco has four boxes labelled K, L, M and N. He places them in a straight line in the order K, L, M, N with K on the left. Marco also has four coloured marbles: one is red, one is green, one is white and one is yellow. He places a single marble in each box, at random. Events A and B are defined as follows.
A: The white marble is in either box L or box M.
B: The red marble is to the left of both the green marble and the yellow marble.
Determine whether or not events A and B are independent.
Rory has 10 cards. Four of the cards have a 3 printed on them and six of the cards have a 4 printed on them. He takes three cards at random, without replacement, and adds up the numbers on the cards. Event \(R\) is 'the sum of the numbers on the three cards is 11'. Event \(S\) is 'the number on the first card taken is a 3'.
(iii) Determine whether events \(R\) and \(S\) are independent. Justify your answer.
(iv) Determine whether events \(R\) and \(S\) are exclusive. Justify your answer.
Q is the event ‘Nicola throws two fair dice and gets a total of 5’. S is the event ‘Nicola throws two fair dice and gets one low score (1, 2 or 3) and one high score (4, 5 or 6)’. Are events Q and S independent? Justify your answer.
Ronnie obtained data about the gross domestic product (GDP) and the birth rate for 170 countries. He classified each GDP and each birth rate as either ‘low’, ‘medium’ or ‘high’. The table shows the number of countries in each category.
| Birth rate | |||
|---|---|---|---|
| GDP | Low | Medium | High |
| Low | 3 | 5 | 45 |
| Medium | 20 | 42 | 12 |
| High | 35 | 8 | 0 |
One of these countries is chosen at random.
One country is chosen at random from those countries which have a medium GDP and then a different country is chosen at random from those which have a medium birth rate.
Suzanne has 20 pairs of shoes, some of which have designer labels. She has 6 pairs of high-heeled shoes, of which 2 pairs have designer labels. She has 4 pairs of low-heeled shoes, of which 1 pair has designer labels. The rest of her shoes are pairs of sports shoes. Suzanne has 8 pairs of shoes with designer labels in total.
(i) Copy and complete the table below to show the number of pairs in each category.
| Designer labels | No designer labels | Total |
|---|---|---|
| High-heeled shoes | 6 | |
| Low-heeled shoes | 4 | |
| Sports shoes | ||
| Total | 20 |
Suzanne chooses 1 pair of shoes at random to wear.
(ii) Find the probability that she wears the pair of low-heeled shoes with designer labels.
(iii) Find the probability that she wears a pair of sports shoes.
(iv) Find the probability that she wears a pair of high-heeled shoes, given that she wears a pair of shoes with designer labels.
(v) State with a reason whether the events ‘Suzanne wears a pair of shoes with designer labels’ and ‘Suzanne wears a pair of sports shoes’ are independent.
In a group of 30 teenagers, 13 of the 18 males watch 'Kops are Kids' on television and 3 of the 12 females watch 'Kops are Kids'.
(i) Find the probability that a person chosen at random from the group is either female or watches 'Kops are Kids' or both.
(ii) Showing your working, determine whether the events 'the person chosen is male' and 'the person chosen watches Kops are Kids' are independent or not.
Bag A contains 4 balls numbered 2, 4, 5, 8. Bag B contains 5 balls numbered 1, 3, 6, 8, 8. Bag C contains 7 balls numbered 2, 7, 8, 8, 8, 8, 9. One ball is selected at random from each bag.
Tim throws a fair die twice and notes the number on each throw.
(i) Tim calculates his final score as follows. If the number on the second throw is a 5 he multiplies the two numbers together, and if the number on the second throw is not a 5 he adds the two numbers together. Find the probability that his final score is
(a) 12,
(b) 5.
(ii) Events A, B, C are defined as follows.
A: the number on the second throw is 5
B: the sum of the numbers is 6
C: the product of the numbers is even
By calculation find which pairs, if any, of the events A, B and C are independent.
Two fair twelve-sided dice with sides marked 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 are thrown, and the numbers on the sides which land face down are noted. Events \(Q\) and \(R\) are defined as follows.
\(Q\): the product of the two numbers is 24.
\(R\): both of the numbers are greater than 8.
Two fair dice are thrown.
Data about employment for males and females in a small rural area are shown in the table.
| Unemployed | Employed | |
|---|---|---|
| Male | 206 | 412 |
| Female | 358 | 305 |
A person from this area is chosen at random. Let \(M\) be the event that the person is male and let \(E\) be the event that the person is employed.
A game is played with an ordinary fair 6-sided die. A player throws the die once. If the result is 2, 3, 4, or 5, that result is the player's score and the player does not throw the die again. If the result is 1 or 6, the player throws the die a second time and the player's score is the sum of the two numbers from the two throws.
(a) Draw a fully labelled tree diagram to represent this information.
Events A and B are defined as follows.
A: the player's score is 5, 6, 7, 8 or 9
B: the player has two throws
(b) Show that P(A) = \(\frac{1}{3}\).
(c) Determine whether or not events A and B are independent.
(d) Find P(B | A').
Events A and B are such that \(P(A) = 0.3\), \(P(B) = 0.8\) and \(P(A \text{ and } B) = 0.4\). State, giving a reason in each case, whether events A and B are
Each of the 180 students at a college plays exactly one of the piano, the guitar, and the drums. The numbers of male and female students who play the piano, the guitar, and the drums are given in the following table.
| Piano | Guitar | Drums | |
|---|---|---|---|
| Male | 25 | 44 | 11 |
| Female | 42 | 38 | 20 |
A student at the college is chosen at random.
There are 400 students at a school in a certain country. Each student was asked whether they preferred swimming, cycling or running and the results are given in the following table.
| Swimming | Cycling | Running | |
|---|---|---|---|
| Female | 104 | 50 | 66 |
| Male | 31 | 57 | 92 |
A student is chosen at random.
Two ordinary fair dice, one red and the other blue, are thrown.
Event \(A\) is 'the score on the red die is divisible by 3'.
Event \(B\) is 'the sum of the two scores is at least 9'.
(a) Find \(P(A \cap B)\).
(b) Hence determine whether or not the events \(A\) and \(B\) are independent.
A total of 500 students were asked which one of four colleges they attended and whether they preferred soccer or hockey. The numbers of students in each category are shown in the following table.
| Soccer | Hockey | Total | |
|---|---|---|---|
| Amos | 54 | 32 | 86 |
| Benn | 84 | 72 | 156 |
| Canton | 22 | 56 | 78 |
| Devar | 120 | 60 | 180 |
| Total | 280 | 220 | 500 |
One of the students is chosen at random. Determine whether the events ‘the student prefers hockey’ and ‘the student is at Amos college or Benn college’ are independent, justifying your answer.
There are 300 students at a music college. All students play exactly one of the guitar, the piano or the flute. The numbers of male and female students that play each of the instruments are given in the following table.
| Guitar | Piano | Flute | |
|---|---|---|---|
| Female students | 62 | 35 | 43 |
| Male students | 78 | 40 | 42 |
Two ordinary fair dice are thrown and the numbers obtained are noted. Event S is ‘The sum of the numbers is even’. Event T is ‘The sum of the numbers is either less than 6 or a multiple of 4 or both’. Showing your working, determine whether the events S and T are independent.