Question 1

Suppose you roll two fair six-sided dice. What is the probability that the sum of the two dice equals 10?

Accepted Answer

$$\frac{3}{36}$$

Question 2

A family is selected at random from a group of 1000 families. 350 families have three persons, 420 have four persons, and 230 have five persons. What is the probability that the selected family has more than three persons?

Accepted Answer

$$\frac{650}{1000}$$

Question 3

If $$A$$ and $$B$$ are mutually exclusive events, which of the following is true?

Accepted Answer

$$P(A \cap B) = 0$$

Question 4

A pre-school class has 7 boys and 5 girls. Two students are selected at random to be 'students of the day.' What is the probability that both students chosen are girls?

Accepted Answer

$$\frac{5}{33}$$

Question 5

If $$P(A) = 0.7$$, $$P(B) = 0.6$$, and $$P(A \cap B) = 0.4$$, what is $$P(A \cup B)$$?

Accepted Answer

$$0.9$$

Question 6

Which of the following statements about probability is FALSE?

Accepted Answer

The probability of an impossible event is 1.

Question 7

A contingency table shows that 350 people are 'Very Happy' and 2016 people were surveyed. What is the probability that a randomly selected person is 'Very Happy'?

Accepted Answer

$$\frac{350}{2016}$$

Question 8

If $$P(E) = 0.3$$, what is the probability of the complement of $$E$$?

Accepted Answer

$$0.7$$

Question 9

Suppose you toss a balanced coin twice. What is the probability that both tosses result in heads?

Accepted Answer

$$\frac{1}{4}$$

Question 10

In a survey, 31 people with 'Above Average' income are 'Not Too Happy', and the total number of people surveyed is 2016. What is the joint probability that a randomly selected person has 'Above Average' income and is 'Not Too Happy'?

Accepted Answer

$$\frac{31}{2016}$$

Question 11

If $$P(A) = 0.5$$, $$P(B) = 0.4$$, and $$A$$ and $$B$$ are mutually exclusive, what is $$P(A \cup B)$$?

Accepted Answer

$$0.9$$

Question 12

A die is rolled. Let $$A be $$the event 'the die shows 5', and $$B be $$the event 'the die shows an even number.' What is $$P(A \cap B)$$?

Accepted Answer

$$0$$

Question 13

If $$P(A) = 0.6$$ and $$P(B|A) = 0.5$$, what is $$P(A \cap B)$$?

Accepted Answer

$$0.3$$

Question 14

A sample space consists of the outcomes {1, 2, 3, 4, 5, 6}. If event $$A is$$ 'rolling a number greater than 4', what is $$P(A)$$?

Accepted Answer

$$\frac{1}{3}$$

Question 15

In a class, the probability that Thelma goes home for the weekend is 0.7, and the probability that Louise goes home is 0.6. The probability that both go home is 0.4. What is the probability that at least one of them goes home?

Accepted Answer

$$0.9$$

Question 16

Which of the following best describes a 'sample space'?

Accepted Answer

The collection of all possible outcomes for an experiment.

Question 17

If $$P(A) = 0.2$$, $$P(B) = 0.5$$, and $$P(A \cap B) = 0.1$$, what is $$P(A|B)$$?

Accepted Answer

$$0.2$$

Question 18

A teacher randomly selects two students from a class of 7 boys and 5 girls. What is the probability that the first student is a girl and the second is a boy?

Accepted Answer

$$\frac{35}{132}$$

Question 19

If $$P(A) = 0.4$$, $$P(B) = 0.5$$, and $$A$$ and $$B$$ are independent, what is $$P(A \cap B)$$?

Accepted Answer

$$0.2$$

Question 20

Which of the following is an example of mutually exclusive events?

Accepted Answer

Rolling a 2 and rolling a 5 on a single die roll.

Fundamentals of Probability and Events in Statistics

Guida di studio - Domande di pratica

Study guide - Flashcard