STATS 7 LEC B: BASIC S...

Ch 8 Topic Quiz (Parts 1 & 2)

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Ch 8 Topic Quiz (Parts 1 & 2)Started: Oct 24 at 6:19pmQuiz Instructions

Flag question: Question 1Question 110 pts

What is the difference between a discrete random variable and a continuous random variable?

Group of answer choices

A discrete random variable can take one of a countable list of values while a continuous random variable can take any value in an interval or a collection of intervals.

A continuous random variable can take one of a countable list of values while a discrete random variable can take any value in an interval or a collection of intervals.

There is no difference

Flag question: Question 2Question 210 pts

Match the examples of random variables with the type of random variable.

Group of answer choices

The width of bay leaves measured in centimeters.

[ Choose ] Discrete random variable Continuous random variable

The number of individuals in a sample of 10 with blood Type A.

[ Choose ] Discrete random variable Continuous random variable

The number of missing teeth per child in an elementary school.

[ Choose ] Discrete random variable Continuous random variable

The amount of sugar (in grams) in an orange.

[ Choose ] Discrete random variable Continuous random variable

Flag question: Question 3Question 310 pts

True or False

Let be the number of male births between 1:00am and 3:00am at a hospital in Orange county. The probability that equals 8 is denoted by .

Group of answer choices

True

False

Flag question: Question 4Question 410 pts

Which of the following are true about a probability distribution function (pdf) for the discrete random variable .

Group of answer choices

A pdf is a table or rule that assigns probabilities to the possible values of X.

P(X=k) is the pdf for some discrete number k.

Both are true.

Flag question: Question 5Question 510 pts

True or False

For a discrete random variable , the cumulative distribution function (cdf) is a table or rule that provides the probabilities from some discrete number k.

Group of answer choices

True

False

Flag question: Question 6Question 610 pts

True or False

We can represent the pdf of a discrete random variable X with a histogram.

Group of answer choices

True

False

Flag question: Question 7Question 710 pts

Which of the following is true about the expected value of a random variable ?

(Two correct answers)

Group of answer choices

It is the sample mean.

It is the mean value of the random variable.

It is the mean value that would be obtained from an infinite number of observations of the random variable X.

Flag question: Question 8Question 810 pts

True or False

Let be a discrete random variable with possible values occurring with probabilities. Then the expected value ofis calculated as

.

Group of answer choices

True

False

Flag question: Question 9Question 910 pts

Select all the following that are true about the variance and standard deviation of a discrete random variable.

(Three correct answers)

Group of answer choices

The positive (or negative) square root of the variance is the standard deviation.

To compute the variance of X, we subtract the mean from each of the values of X, square them, and then multiply by the probabilities and then sum them up.

The standard deviation of a random variable can be positive or negative.

The standard deviation of X is the positive square root of the variance of X.

The standard deviation of a discrete random variable quantifies how spread out the possible values of the random variable are, weighted by how likely each value is to occur.

Flag question: Question 10Question 1010 pts

Letandbe independent discrete random variables and let and .Using properties of linear combinations of random variables and assumingare positive or negative constants, match the following.

Group of answer choices

E[L]

[ Choose ] aE[X]+bE[Y] + c Var[L] + 1 aE[X]+bE[Y] + c^2 aE[X]+bE[Y] a^2Var[X]+b^2Var[Y]

E[M]

[ Choose ] aE[X]+bE[Y] + c Var[L] + 1 aE[X]+bE[Y] + c^2 aE[X]+bE[Y] a^2Var[X]+b^2Var[Y]

Var[L]

[ Choose ] aE[X]+bE[Y] + c Var[L] + 1 aE[X]+bE[Y] + c^2 aE[X]+bE[Y] a^2Var[X]+b^2Var[Y]

Var[M] + 1

[ Choose ] aE[X]+bE[Y] + c Var[L] + 1 aE[X]+bE[Y] + c^2 aE[X]+bE[Y] a^2Var[X]+b^2Var[Y]

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Attempt due: Oct 26 at 11:59pm

9 Minutes, 10 Seconds