ISDS 361B Final

A health conscious student faithfully wears a device that tracks his steps. Suppose that the distribution of the number of steps he takes in a day is normally distributed with a mean of 10,000 and a standard deviation of 1,500 steps. What percent of the days does he exceed 13,000 steps? a. 5% b. 97.72% c. 95% d. 2.28%

2.28%

The random variable X is known to be uniformly distributed between 2 and 12. Compute the standard deviation of X. a. 8.333 b. 12 c. 2.887 d. 3.464

2.887

The random variable X is known to be uniformly distributed between 2 and 12. Compute E(X), the expected value of the distribution. a. 4 b. 7 c. 5 d. 6

7

Which statement is true about mutually exclusive events? a. If events A and B cannot occur at the same time, they are called mutually exclusive. b. If either event A or event B must occur, they are called mutually exclusive. c. P(A) + P(B) = 1 for any events A and B that are mutually exclusive. d. None of these choices are correct.

If events A and B cannot occur at the same time, they are called mutually exclusive.

In a normal distribution, which is greater, the mean or the median? a. Mean b. Median c. Neither the mean or the median (they are equal) d. Cannot be determined with the information provided.

Neither the mean or the median (they are equal)

The __________ probability distribution can be used to estimate the number of vehicles that go through an intersection during the lunch hour. a. triangular b. Poisson c. binomial d. normal

Poisson

Which of the following statements is correct? a. The binomial distribution is a discrete probability distribution and the normal distribution is a continuous probability distribution. b. The binomial and normal distributions are both discrete probability distributions. c. The binomial and normal distributions are both continuous probability distributions. d. The binomial distribution is a continuous probability distribution, and the normal distribution is a discrete probability distribution.

The binomial distribution is a discrete probability distribution and the normal distribution is a continuous probability distribution.

Which of the following is a discrete random variable? a. The height of water-oak trees b. The number of times a student guesses the answers to questions on a certain test c. The amount of mercury found in fish caught in the Gulf of Mexico d. The amount of gasoline purchased by a customer

The number of times a student guesses the answers to questions on a certain test

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

The standard deviation must be 1.

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 a. continuous random variable. b. discrete random variable. c. complex random variable. d. categorical random variable.

continuous random variable.

A variable that can only take on specific numeric values is called a a. discrete random variable. b. complex random variable. c. continuous random variable. d. categorical variable.

discrete random variable.

All of the following are examples of discrete random variables except a. marital status. b. time. c. number of tickets sold. d. population of a city.

marital status.

If a z-score is zero, then the corresponding x-value must be equal to the a. standard deviation. b. median. c. mean. d. mode.

mean.

Probability is the: a. numerical measure of the likelihood that an event will occur. b. chance that an event will not happen. c. number of successes divided by the number of failures. d. number of successes divided by the standard deviation of the distribution.

numerical measure of the likelihood that an event will occur.

An initial estimate of the probabilities of events is a __________ probability. a. empirical b. conditional c. prior d. posterior

prior

Bayes' theorem is a method used to compute __________ probabilities. a. prior b. empirical c. posterior d. conditional

prior

A __________ describes the range and relative likelihood of all possible values for a random variable. a. probability b. probability mass function of an event c. probability distribution for a random variable d. density function

probability distribution for a random variable

A joint probability is the a. sum of the probabilities of two independent events. b. sum of the probabilities of two events. c. probability of the union of two events. d. probability of the intersection of two events.

probability of the intersection of two events.

Sample space is a. a process that results in some outcome. b. the collection of events c. a subgroup of a population/the likelihood of an outcome. d. the collection of all possible outcomes.

the collection of all possible outcomes.

All the events in the sample space that are not part of the specified event are called a. simple events. b. joint events. c. the complement of the event. d. independent events.

the complement of the event.

All the events in the sample space that are not part of the specified event are called a. the complement of the event. b. simple events. c. independent events. d. joint events.

the complement of the event.

The center of a normal curve is a. the mean of the distribution. b. equal to the standard deviation. c. always a positive number. d. always equal to zero.

the mean of the distribution.

The event containing the outcomes belonging to A or B or both is the __________ of A and B. a. Venn diagram b. complement c. union d. intersection

union