Random Variables

Random Variables

Multiple Choice

State why the example does or does not describe a random variable.

The letters "A", "B", "C", "D", "E", and "F" are written on six slips of paper, and the slips are placed into a hat. Assign A = 1, B = 2, C = 3, D = 4, E = 5 , and F = 6. S is the random selection of a slip of paper.

• S is a random variable. It has a single value for each outcome in an experiment.

• S is a random variable. A random variable is denoted with a capital letter.

• S is a random variable. It is not random.

• S is not a random variable. It is not determined by chance.

Multiple Choice

State why the example does or does not describe a random variable.

Label five slips of paper as A, B, C, D, and E. S is the random selection of a slip of paper.

• S is a random variable. A random variable is denoted with a capital letter.

• S is not a random variable, the outcome of the experiment is not numerical.

• S is a random variable. It has five possible outcomes.

• S is not a random variable. It is not determined by chance.

Multiple Choice

A random variable is defined by a rule that assigns a _______________ to every outcome in a sample space.

• number

• letter

• Event

• probability

Multiple Choice

A couple has four children. Let "b" = the number of boys they have. What are the possible outcomes of "b"?

• {0, 1, 2, 3, 4}

• {1, 2, 3, 4}

• {boy, girl}

• {0, 1, 2, ..... 16}

Multiple Choice

Assume the “student” in the situation is chosen at random, and state whether the variable is discrete or continuous.

• The number of books the student has in his or her bag.

• Discrete random variable

• Continuous random variable

• Neither discrete nor continuous

Multiple Choice

A point is randomly selected from the interior of a square. Let x denote the distance from the lower left-hand corner A of the square to the selected point. Are the possible values of x a discrete or continuous variable?

• discrete random variable

• continuous random variable

• neither discrete random variable nor continuous random variable

Multiple Choice

Experiment: Ask 50 shampoo users. Let X be the number of satisfied users.  What are the possible values of X?

•  $x\le50$ 

•  $x=1,2,3,4,5,...,50$ 

•  $x=0,1,2,3,4,...,50$ 

Multiple Choice

Choose a number between 1 and 10, multiply it by the age, in years, of the person next to you and add your own age in years. Do this for 5 people. B is the average of the results from the six trials. Is B a random variable?

• Yes

• No

Multiple Choice

Which of the following is a continuous random variable?

• The number of students online.

• The time you spent in praying.

• The number of COVID-19 cases.

• The number of front liners in your city/municipality.