Math 2228 Exam 2

Two six-sided die are rolled. The probability of the sum of the two die being a 10 is _____________.

0.083

A novel on the Amazon.com web site has the following ratings, in number of stars, from reviewers: # of Stars Frequency 1 7 2 4 3 20 4 9 5 10 What is the probability that a randomly selected review is more than three stars?

0.38

The following table shows the number of pieces of junk mail that arrives in my mailbox each day. Mean of this distribution is ______________________ #of Pieces of Junk Mail Frequency 2 2 3 14 4 6 5 16 6 12

4.44

____________________ probability requires that you count the frequency that an event occurs through an experiment and calculate the probability from the experiment's relative frequency distribution.

Classical

_____________________ probability is used when we rely on experience and intuition to estimate the likelihood of an event.

Empirical

You can conclude that, because events are not independent, they will be mutually exclusive.

False

A smaller standard deviation for the normal probability distribution results in ______________________

a skinnier curve that is tighter and taller around the mean.

Which of the following probability distribution is not continuous?

binomial

__________________ probability is used when we know the number of possible outcomes of the event of interest and the total number of possible outcomes in the sample space.

classical

The law of large numbers states that when an experiment is conducted a large number of times, the ______________ probabilities of the process will converge to the _____________________ probabilities.

empirical, classical

A normal probability distribution's standard deviation (σ) completely describes it's shape.

false

An expected value is another term for the standard deviation of a probability distribution.

false

Events A and B are considered to be independent events if the probability of event A given the occurrence of event B is equal to the probability of Event A occurring.

false

For continuous distributions, the probability that is less than or equal to a value is not the same as the probability that x is less than that value.

false

In a binomial experiment, the number of successes can exceed the number of trials.

false

The standard deviation of the continuous uniform distribution is equal to the mean of this distribution.

false

The shape of the uniform probability distribution is ____________________________

flat and straight

The _____________ of a discrete probability distribution measures the dispersion of each outcome of the random variable from the mean of the distribution.

standard deviation

According to the Empirical Rule, if a distribution follows a bell-shaped, symmetrical curve centered around the mean, approximately 68, 95, and 99.7 percent of its values will fall within one, two, and three standard deviations above and below the mean respectively.

true

An event with a single outcome in its most basic form that cannot be simplified is known as a simple probability.

true

Consider the following events: Event A = The survey respondent is a registered Republican. Event B = The survey respondent lives in Ohio. Events A and B are mutually exclusive.

true

In order to use a normal approximation to the binomial distribution, np(1-p)≥10

true

Rating the satisfaction of a hotel room on a 1-5 scale is an example of a discrete random variable.

true

Testing whether a part is defective or not defective after it has been manufactured would be best described using a binomial probability distribution.

true

The area under the curve of the normal probability distribution is always equal to 1.0.

true

The complement to Event A is defined as all of the outcomes in the sample space that are not part of event A.

true

The left and right ends of the normal probability distribution extend indefinitely, never quite touching the horizontal axis.

true

The mean and the standard deviation for discrete probability distributions are useful when comparing two different distributions.

true

Which of the following is not a characteristic of a binomial distribution?

The probability of a success must exceed the probability of a failure.

Which of the following is not a condition of a discrete probability distribution?

The probability of a success must exceed the probability of a failure.