Business and Economic Stats Ch 5

The probability distribution for the number of goals the Lions soccer team makes per game is given below. Number Of Goals 0 1 2 3 Probability 0.05 0.15 0.30 0.25 0.15 What is the probability that in a given game the Lions do not score more than 2 goals?

0.50

The following represents the probability distribution for the daily demand of computers at a local store. Demand Probability 0.15 0.25 0.35 0.20 0.05 The probability of having a demand for at least two computers is

0.60.

Random variable x has the probability function f(x) = X/6, for x = 1, 2 or 3 The expected value of + is

2.333.

Consider the probability distribution below. A(x). 2 10 20 30 40 3 The expected value of x equals

23

Which of the following is a characteristic of an experiment where the binomial probability distribution is applicable?

Exactly two outcomes are possible on each trial

The weight of an object is an example of

a continuous random variable

A continuous random variable may assume

any numerical value in an interval or collection of intervals.

The Poisson probability distribution is a _________ probability distribution.

discrete

Which of the following is a required condition for a discrete probability function?

£(x) = 1 for all values of x

The probability distribution for the daily sales at Michael's Co. is given below. Daily Sales ($1,000s) 40 50 60 Probability 0.2 0.4 0.3 The expected daily sales are

$53,000.

Assume that you have a binomial experiment with p = 0.4 and a sample size of 50. The variance of this distribution is

12

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. 0 2 f(x) 0.80 0.15 0.04 0.01 The mean and the standard deviation for the number of electrical outages (respectively) are

0.26 and 0.577.

Oriental Reproductions, Inc. is a company that produces handmade carpets with oriental designs. The production records show that the monthly production has ranged from 1 to 5 carpets. The production levels and their respective probabilities are shown below. Production Per Month 2 Probability 0.01 0.04 0.10 0.80 0.05 The standard deviation for the production is ) 4.32. С 0.374 ) 0.612.

0.612.

The probability distribution for the daily sales at Michael's Co. is given below. Daily Sales (In $1,000s) Probability 40 01 50 0.4 60 0.3 70 0.2 The probability of having sales of no more than $60,000 is

0.8

A 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 Coffee 0 1 v 18 3 Frequency 700 900 500 400 2.500 21 The variance of the number of cups of coffee

1.06.

A 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 Coffee Frequency 700 900 2 500 3 400 2.500 x 18 21 24 27 30 The expected number of cups of coffee is

1.24.

Roth is a con to 6 The number of new ing firm. The mu Äber of ni V di they have obtained each month has ranged from 0 shown below. Number of New Clients Probability 0 0.05 1 0.10 2 0.15 3 0.30 4 0.25 5 0.10 6 0.05

1.45

The following represents the probability distribution for the daily demand of computers at a local store Demand 0 1 2 3 Probability 0.15 0.25 0.35 0.2 0.05 The expected daily demand is

1.75

The random variable x is the number of occurrences of an event over an interval of ten minutes. It can be assumed that the probability of an occurrence is the same in any two time periods of an equal length. It is known that the mean number of occurrences in ten minutes is 5.3. The expected value of the random variable x is

5.3.

Twenty percent of the students in a class of 400 are planning to go to graduate school. The standard deviation of this binomial distribution is

8

Consider the probability distribution below. Ax) 10 2 4 20 30 40 The variance of r equals

81.

A name closely associated with the binomial probability distribution is

Bernoulli.

The ________ probability function is based in part on the counting rule for combinations.

Hypergeometric

The expected value of a random variable is

None of these altemnatives is correct.

The expected value for a binomial distribution is given by equation

Np

The random variable a is the number of occurrences of an event over an interval of ten minutes. It can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. It is known that the mean number of occurrences in ten minutes is 5.3. Which of the following discrete probability distributions' properties are satisfied by random variable x?

Poisson

Which of the following properties of a binomial experiment is called the stationarity assumption?

The probability of success is the same for each trial.

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

expected value

A description of the distribution of the values of a random variable and their associated probabilities 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.