Quiz 4

The number of electrical outages in a city varies from day to day. Assume that the number of electrical outages (x) in the city has the following probability distribution. xf(x) 00.80 10.15 20.04 30.01 The mean and the standard deviation for the number of electrical outages (respectively) are

.26 and .577

Exhibit 5-1The following represents the probability distribution for the daily demand of microcomputers at a local store. DemandProbability 00.1 10.2 20.3 30.2 40.2 Refer to Exhibit 5-1. The probability of having a demand for at least two microcomputers is

.7

Exhibit 5-2The probability distribution for the daily sales at Michael's Co. is given below. Daily Sales ($1,000s)Probability 400.1 500.4 600.3 700.2 Refer to Exhibit 5-2. The probability of having sales of at least $50,000 is

.90

Exhibit 5-3The probability distribution for the number of goals the Lions soccer team makes per game is given below. Number of GoalsProbability 00.05 10.15 20.35 30.30 40.15 Refer to Exhibit 5-3. What is the probability that in a given game the Lions will score at least 1 goal?

.95

Exhibit 5-7A sample of 2,500 people was asked how many cups of coffee they drink in the morning. You are given the following sample information. Cups of CoffeeFrequency 0700 1900 2600 3300 2,500 Refer to Exhibit 5-7. The variance of the number of cups of coffee is

.9798

The expected value for a binomial probability distribution is

E(x)=np

The number of customers that enter a store during one day is an example of

a discrete random variable

The weight of an object, measured to the nearest gram, is an example of

a discrete random variable

A continuous random variable may assume

any value in an interval or collection of intervals

An experiment consists of measuring the speed of automobiles on a highway by the use of radar equipment. The random variable in this experiment is speed, measured in miles per hour. This random variable is a

continuous random variable

The Poisson probability distribution is a

discrete probability distribution

A random variable that can assume only a finite number of values is referred to as a(n)

discrete random variable

An experiment consists of making 80 telephone calls in order to sell a particular insurance policy. The random variable in this experiment is the number of sales made. This random variable is a

discrete random variable

The binomial probability distribution is used with

discrete random variable

A measure of the average value of a random variable is called a(n)

expected value

Which of the following is not a required condition for a discrete probability function?

f(x) ≤ 0 for all values of x

To compute the probability that in a random sample of n elements, selected without replacement, we will obtain x successes, we would use the

hypergeometric probability distribution

The function used to compute the probability of x successes in n trials, when the trials are dependent, is the

hypergeometric probability function

The expected value of a discrete random variable

is the average value for the random variable over many repeats of the experiment

The standard deviation of a binomial distribution is

none of the alternative answers are correct

Exhibit 5-3The probability distribution for the number of goals the Lions soccer team makes per game is given below. Number of GoalsProbability 00.05 10.15 20.35 30.30 40.15 Refer to Exhibit 5-3. What is the probability that in a given game the Lions will score no goals?

none of the answers are correct

Which of the following is(are) required condition(s) for a discrete probability function?

none of the answers are correct

The binomial probability distribution is most symmetric when

p equals .5

A description of how the probabilities are distributed over the values the random variable can assume is called a

probability distribution

The key difference between the binomial and hypergeometric distribution is that with the hypergeometric distribution the

probability of success changes from trial to trial

In a binomial experiment, the

probability of success does not change from trial to trial

A numerical description of the outcome of an experiment is called a

random variable

A weighted average of the value of a random variable, where the probability function provides weights is known as

the expected value

The standard deviation is the

the positive square root of the variance

Which of the following is not a property of a binomial experiment?

the probabilities of the two outcomes can change from one trial to the next

Which of the following is not a characteristic of an experiment where the binomial probability distribution is applicable?

the trials are dependent

Which of the following statements about a discrete random variable and its probability distribution are true?

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

A production process produces 2% defective parts. A sample of five parts from the production process is selected. What is the probability that the sample contains exactly two defective parts?

.0038

In a binomial experiment the probability of success is 0.06. What is the probability of two successes in seven trials?

.0554

Exhibit 5-5AMR is a computer-consulting firm. The number of new clients that they have obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below. Number of New ClientsProbability 00.05 10.10 20.15 30.35 40.20 50.10 60.05 Refer to Exhibit 5-5. The standard deviation is

1.431

Exhibit 5-3The probability distribution for the number of goals the Lions soccer team makes per game is given below. Number of GoalsProbability 00.05 10.15 20.35 30.30 40.15 Refer to Exhibit 5-3. The expected number of goals per game is

2.35

Exhibit 5-6Probability Distribution xf(x) 10.2 20.3 30.4 40.1 Refer to Exhibit 5-6. The expected value of x equals

24

Exhibit 5-5AMR is a computer-consulting firm. The number of new clients that they have obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below. Number of New ClientsProbability 00.05 10.10 20.15 30.35 40.20 50.10 60.05 Refer to Exhibit 5-5. The expected number of new clients per month is

3.05

Excel's POISSON function has how many arguments?

4

Twenty percent of the students in a class of 100 are planning to go to graduate school. The standard deviation of this binomial distribution is

4

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

50

Exhibit 5-2The probability distribution for the daily sales at Michael's Co. is given below. Daily Sales ($1,000s)Probability 400.1 500.4 600.3 700.2 Refer to Exhibit 5-2. The expected daily sales are

56,000

Exhibit 5-4A local bottling company has determined the number of machine breakdowns per month and their respective probabilities as shown below. Number of BreakdownsProbability 00.12 10.38 20.25 30.18 40.07 Refer to Exhibit 5-4. The probability of at least 3 breakdowns in a month is

None of the alternative answers are correct

Exhibit 5-4A local bottling company has determined the number of machine breakdowns per month and their respective probabilities as shown below. Number of BreakdownsProbability 00.12 10.38 20.25 30.18 40.07 Refer to Exhibit 5-4. The probability of no breakdowns in a month is

None of the alternative answers are correct

The expected value of a random variable is the

None of the answers are correct

In the textile industry, a manufacturer is interested in the number of blemishes or flaws occurring in each 100 feet of material. The probability distribution that has the greatest chance of applying to this situation is the

Poisson Distribution

The weight of an object, measured in grams, is an example of

a continuous random variable

The Poisson probability distribution is used with

a discrete random variable

A probability distribution showing the probability of x successes in n trials, where the probability of success does not change from trial to trial, is termed a

binomial probability distribution

If you are conducting an experiment where the probability of a success is .02 and you are interested in the probability of 4 successes in 15 trials, the correct probability function to use is the

binomial probability function