BUS Stats Test 2

How to find expected value

N*P

How to find Variance given expected value

N*P(1-P)

Excel's _____ function can be used to compute the expected value of a discrete random variable. SUMPRODUCT AVERAGE MEDIAN

SUMPRODUCT

What is the conditional probability of P(A|B)

P(AintersectionB)/P(B) intersection is equal to upside down U

If P(A)= .80. P(B)= .65, and P(AintersectionB)=.78; then P(B|A)=

.98; P(B|A)= P(AintersectionB)/P(B) .78/.65=.98

The assembly time for a product is uniformly distributed between 6 and 10 minutes. The probability of assembling the product in less than 6 minutes is _____. 0 .5 .15 1

0

The expected value of a random variable is the _____. most probable value simple average of all the possible values mean value

mean value

The standard deviation is the _____. variance squared square root of the sum of the deviations from the mean positive square root of the variance same as the expected value

positive square root of the variance

If two events are independent, then they must be mutually exclusive the sum of their prob are 1 the prob of their intersection is zero the product of their probabilities gives their intersection

the product of their probabilities gives their intersection.

Probability for Intersection B is ________ for disjoint events or mutually exclusive events.

zero; if A and B are mutually exclusive then there is no joint or common part hence the joint probability should equal 0

If P(A)= .28, P(B)= .83, and P(AintersectionB)=.24; then P(AUB)=

.87; .28+.83-.24=.87

If A and B are mutually exclusive events with P(A)= .3 and P(B)= .5; then P(AUB)=

.8; because AUB= P(a)+P(B)-P(AintersectionB) .3+.5-0=.8

Assume that you have a binomial experiment with p = 0.5 and a sample size of 100. The expected value of this distribution is _____. .5 .3 50

50

AintersectionB means

A and B together

normal probability distribution

A continuous probability distribution determined by its mean and standard deviation .

bivariate distribution

A probability distribution that provides probabilities of combinations of two random variables.

expected value

The mean of a probability distribution.

Which of the following is NOT a characteristic of an experiment where the binomial probability distribution is applicable? The experiment has a sequence of n identical trials. Exactly two outcomes are possible on each trial. The trials are dependent.

The trials are dependent.

Which of the following statements about a discrete random variable and its probability distribution is true? Negative values of f(x) are allowed if ∑f(x) = 1. Values of f(x) must be greater than or equal to zero. The values of f(x) increase to a maximum point and then decrease.

Values of f(x) must be greater than or equal to zero.

standard deviation

a computed measure of how much scores vary around the mean score; square root of variance

When using Excel's BINOM.DIST function, one should choose TRUE for the fourth input if _____. a probability is desired a cumulative probability is desired the expected value is desired

a cumulative probability is desired

Variance

a measure of the dispersion of a random variable

Variance is _____. a measure of the average, or central value of a random variable a measure of the dispersion of a random variable the square root of the standard deviation

a measure of the dispersion of a random variable

random variable

a numerical description of the outcome of an experiment

continuous probability distribution

a probability distribution showing all the possible outcomes and associated probabilities for a given event; can only find range/interval probability

When using Excel's BINOM.DIST function, one should choose FALSE for the fourth input if _____. a probability mass function is desired a cumulative probability is desired the expected value is desired

a probability mass function is desired

The mean of a standard normal probability distribution_____. is always equal to 1 can be any value as long as it is positive can be any value always equal to 0

always equal to 0

Highway patrol officers measure the speed of automobiles on a highway using radar equipment. The random variable in this experiment is speed, measured in miles per hour. This random variable is a _____. discrete random variable continuous random variable None of the answers is correct.

continuous random variable

A marketing manager instructs his team to make 80 telephone calls to attempt to sell an insurance policy. The random variable in this experiment is the number of sales made. This random variable is a _____ discrete random variable continuous random variable None of the answers is correct.

discrete random variable

Binomial Distribution (Conditions)

discrete trials, two types of outcomes, and probability is fixed

Union: AUB means

either A or B or both; P(A)+P(B)-P(AintersectionB)