OBA 311 midterm

The weight of an object is an example of

a continuous random variable.

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

a discrete random variable

The Poisson probability distribution is used with

a discrete random variable.

The binomial probability distribution is used with

a discrete random variable.

Each individual outcome of an experiment is called

a sample point.

When n-1 is used in the denominator to compute variance,

the data set is a sample.

Which of the following is a required condition for a discrete probability function? a. ∑f(x) = 0 for all values of x b. f(x) 1 for all values of x c. f(x) < 0 for all values of x d. ∑f(x) = 1 for all values of x

∑f(x) = 1 for all values of x

Which of the following is not a characteristic of the normal probability distribution? a. The mean, median, and the mode are equal b. The mean of the distribution can be negative, zero, or positive c. The distribution is symmetrical d. The standard deviation must be 1

The standard deviation must be 1

A deterministic model is one in which all model input information is either known or assumed to be known with certainty. True or False?

True

In interval estimation, as the sample size becomes larger, the interval estimate

becomes narrower

The z score for the standard normal distribution

can be either negative or positive.

A manager at Gampco Inc. wishes to know the company's revenue and profit in its previous quarter. Which of the following business analytics will help the manager?

descriptive analytics

Predictive analytics is

detects patterns in historical data and extrapolates them forward in time.

Which of the following allow meaningful comparison of ranges, averages and other statistics?

interval data

In a standard normal distribution, the

mean is 0 and the standard deviation is 1

In a standard normal distribution, the range of values of z is from

minus infinity to infinity

The intersection of two mutually exclusive events

must always be equal to 0.

The variance Var(x) for the binomial distribution is given by equation

np(1 - p)

The expected value for a binomial distribution is given by equation

np.

µ is an example of a

population parameter.

A trader who wants to predict short-term movements in stock prices is likely to use ( ) analytics.

predictive

The probability distribution of all possible values of the sample proportion is the

sampling distribution of p bar

As the sample size increases, the

standard error of the mean decreases

For a continuous random variable x, the probability density function f(x) represents

the height of the function at x.

For a uniform probability density function,

the height of the function is the same for each value of x.

The highest point of a normal curve occurs at

the mean.

The sample space refers to

the set of all possible experimental outcomes.

Larger values of the standard deviation result in a normal curve that is

wider and flatter.

If we change a 95% confidence interval estimate to a 99% confidence interval estimate, we can expect the

width of the confidence interval to increase

The probability distribution of all possible values of the sample mean x bar is

the sampling distribution of x bar

he closer the sample mean is to the population mean,

the smaller the sampling error

For a normal distribution, a negative value of z indicates

the z is to the left of the mean

Two events are mutually exclusive if

they have no sample points in common

Which of the following is an example of a measure of continuous metrics?

weight and volume of a sheet of steel

A standard normal distribution is a normal distribution

with a mean of 0 and a standard deviation of 1

For any continuous random variable, the probability that the random variable takes on exactly a specific value is

0

In a standard normal distribution, the probability that Z is greater than zero is

0.5

The sum of the probabilities of two complementary events is

1.0

A continuous random variable is uniformly distributed between a and b. The probability density function between a and b is

1/(b - a)

Which of the following is not a characteristic of the normal probability distribution? a. Symmetry b. The total area under the curve is always equal to 1. c. 99.72% of the time the random variable assumes a value within plus or minus 1 standard deviation of its mean d. The mean is equal to the median, which is also equal to the mode.

99.72% of the time the random variable assumes a value within plus or minus 1 standard deviation of its mean

he union of events A and B is the event containing all the sample points belonging to

A or B or both.

Which of the following is a characteristic of an experiment where the binomial probability distribution is applicable? a. The experiment has at least two possible outcomes b. Exactly two outcomes are possible on each trial c. The trials are dependent on each other d. The probabilities of the outcomes changes from one trial

Exactly two outcomes are possible on each trial

Following are the components of a data set containing purchase details of a shoe manufacturing company. Identify the ratio data. A) Item Number B) Rank of suppliers C) Item cost D) Arrival Date

Item cost

As the sample size becomes larger, the sampling distribution of the sample mean approaches a

Normal distribution

Events A and B are mutually exclusive. Which of the following statements is also true? a. A and B are also independent. b. P(A union B) = P(A)P(B) c. P(A union B) = P(A) + P(B) d. P(A intersect B) = P(A) + P(B)

P(A union B) = P(A) + P(B)

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. Which of the following discrete probability distributions' properties are satisfied by random variable x?

Poisson

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.

If one wanted to find the probability of ten customer arrivals in an hour at a service station, one would generally use the

Poisson probability distribution

Which of the following is not a property of a binomial experiment? a. The experiment consists of a sequence of n identical trials b. Each outcome can be referred to as a success or a failure c. The probabilities of the two outcomes can change from one trial to the next d. The trials are independent

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

Which of the following is a characteristic of the standard normal probability distribution? a. The mean, median, and the mode are not equal b. The distribution is not symmetrical c. The standard deviation must be 0 d. The standard deviation must be 1

The standard deviation must be 1

For a population with any distribution, the form of the sampling distribution of the sample mean is

always normal for large sample sizes

Any process that generates well-defined outcomes is

an experiment.

A continuous random variable may assume

any numerical value in an interval or collection of intervals

Whenever the population has a normal probability distribution, the sampling distribution of is a normal probability distribution for

any sample size

The uniform, normal, and exponential distributions

are all continuous probability distributions.

Nominal data:

are sorted into categories according to specified characteristics.

As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution

becomes smaller

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

In an experiment, events A and B are mutually exclusive. If P(A) = 0.6, then the probability of B

cannot be larger than 0.4.

The standard deviation of a normal distribution

cannot be negative

An experiment consists of determining the speed of automobiles on a highway by the use of radar equipment. The random variable in this experiment is a

continuous random variable

The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects where order of selection is important is called the

counting rule for permutations.

In point estimation

data from the sample is used to estimate the population parameter

As the sample size increases, the margin of error

decreases

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 appropriate probability distribution for the random variable is

discrete

The Poisson probability distribution is a

discrete probability distribution

A simple random sample from an infinite population is a sample selected such that

each element is selected independently and from the same population

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

expected value

An exponential probability distribution

is a continuous distribution.

The standard deviation of a standard normal distribution

is always equal to one

The mean of a standard normal probability distribution

is always equal to zero

The center of a normal curve is

is the mean of the distribution

The value added to and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the

margin of error

If the mean of a normal distribution is negative, a. the standard deviation must also be negative. b. the variance must also be negative. c. a mistake has been made in the computations, because the mean of a normal distribution cannot be negative. d. none of these alternatives is correct.

none of these alternatives is correct

Convenience sampling is an example of

nonprobabilistic sampling

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

probability distribution

Sampling distribution of x bar is the

probability distribution of the sample mean

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

random variable

A negative value of z indicates that

the number of standard deviations of an observation is to the left of the mean

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

the probability of success changes from trial to trial

If two events are independent, then

the product of their probabilities gives their intersection.

A uniform probability distribution is a continuous probability distribution where the probability that the random variable assumes a value in any interval of equal length is

the same for each interval

For a normal distribution, a positive value of z indicates that

the sample mean is larger than the population mean

In interval estimation, the t distribution is applicable only when

the sample standard deviation is used to estimate the population standard deviation