BUS 245 Test 2

Kareem is trying to decide which college to attend full time next year. Kareem believes there is a 55% chance that he will attend State College and a 33% chance that he will attend Northern University. The probability that Kareem will attend either State or Northern is ___________. - 0.18 - 0.88 - 0.22 - 0.55

- 0.88

At a local restaurant 20% of the customers order the chef's special. The restaurant expects 230 customers tonight. The expected number of chef's specials that will be ordered is _______________. Fill in blank.

46

A subset of the sample space is called a/an ____________. Fill in blank.

An Event - is a subset of the sample space.

The complement of event A within the sample space 'S' contains: - All outcomes in A that are not in S - All outcomes in S that are not in A - All outcomes in A that are in S - All outcomes in S that are in A

- All outcomes in S that are not in A

A probability based on logical analysis rater than on observation or personal judgement is BEST referred to as a(n): - Empirical probability - Classical probability - Correlated probability - Subjective probability

- Classical probability Often used in games of chance. Based on the assumption that all outcomes are equally likely.

A probability based on personal judgement rather than on observation or logical analysis is best referred to as a(n). - Classical probability - Correlated probability - Subjective probability - Empirical probability

Subjective probability

A sandwich shop fills 4 customer orders on average every minute during the busy lunch hour. What's the probability that the shop fills exactly the average number of orders -- 4 orders -- during any one-minute period? (Use at least 4 decimal places in your calculations.) - 0 - 0.195 - 0.156 - 0.018

- 0.195 The variable X = number of orders filled during one minute is Poisson since there's no clear maximum number of orders that can be filled. The average mu is 4 orders. (0.0183)(256) / 24 = 0.1952

When rolling a pair of dice and summing the two values rolled, which of the following are exhaustive events? - A sum of 9 or more and a sum of 7 or less - A sum of 7 or more and a sum of 6 or less - A sum of 6 or more and a sum of 8 or less - An even number and an odd number

- A sum of 7 or more and a sum of 6 or less - A sum of 6 or more and a sum of 8 or less - An even number and an odd number [ Exhaustive - When all possible outcomes of an experiment are included in the events. ]

Which of the following are examples of a binomial experiment? - Ask customers how much they spend on an average trip to a grocery store - Ask customers at a movie theater if they spent 20$ or more on concessions - Ask investors if they are risk adverse, risk neutral, or risk loving - Ask randomly-selected people whether they are members of Facebook Check all that apply.

- Ask customers at a movie theater if they spent 20$ or more on concessions - Ask randomly-selected people whether they are members of Facebook

Which of the following BEST represents an empirical probability? - The probability of rolling a '2' on a single die is 1/6. - Based on past data, a manager believes there is a 70% chance of retaining an employee for at least one year. - The probability of tossing a head on a coin is 0.5. - A skier believes she has a 0.10 chance of winning a gold medal.

- Based on past data, a manager believes there is a 70% chance of retaining an employee for at least one year. Empirical Probability - Are calculated from observed data.

Events that cannot both occur on the same trial of an experiment are mutually ___________ events. Fill in blank.

- Mutually exclusive.

A Poisson random variable describes the number of successes of a certain event - Over a given interval of time or in space - When the probability of success changes from trial to trial - In a given number of trials

- Over a given interval of time or in space

The addition rule for two events A and B is? - P(AuB) = P(A) x P(B|A) - P(AnB) = P(A) + P(B) + P(A|B) - P(AuB) = P(A) + P(B) - P(AnB) - P(AuB) = P(A) + P(B)

- P(AuB) = P(A) + P(B) - P(AnB)

The expected value of a distribution is also referred to as the: - Population standard deviation - Population covariance - Population variance - Population mean

- Population mean

When calculating the probability of x successes in n trials of a binomial experiment, the probability of success and the probability of failure - Will be less than one when they are summed together - Need to be adjusted when x is zero - Remain the same, even when a probability is calculated for a different value of x - Can both be either negative of positive values, depending on the situation

- Remain the same, even when a probability is calculated for a different value of x

A(n) __________ of an experiment contains all possible outcomes of the experiment. - Event - Intersection - Simple Event - Sample Space

- Sample Space: denoted by 'S', of an experiment contains all possible outcomes of the experiment.

In the following scenarios, indicate those that describe a Poisson random variable. Check ALL that apply. - The number of customers who purchase concessions over the next hour at a movie theater - The number of leaks in a specified stretch of a pipeline - The number of customers in a sample of 20 who use a credit card to make a purchase at a local pharmacy - The number of mortgage applicants who receive a loan in a sample of 10 applicants.

- The number of leaks in a specified stretch of a pipeline - The number of customers who purchase concessions over the next hour at a movie theater

All of the following are characteristics of a Poisson process EXCEPT: - The number of successes within an interval equals any integer between zero and infinity - The number of successes in n trials is an integer between 0 and n - The numbers of successes in nonoverlapping intervals are independent - The probability that success occurs in any interval is the same for all intervals of equal size

- The number of successes in n trials is an integer between 0 and n

To calculate the probability of the union of two mutually exclusive events A and B, - We add the probability of A to the probability of B, and then subtract the complement of A. - We add the probability of A to the probability of B. - We add the probability of A to the probability of B, and then subtract the complement of B. - We add the probability of A to the probability of B, and then subtract the (nonzero) probability of the intersection of A and B.

- We add the probability of A to the probability of B.

Calculate 5!

5x4x3x2 = 120

Dimitri is the coach of the high school mathletes team. There are 8 mathletes, but only 5 may represent the school at the upcoming math tournament. Dimitri can choose 5 mathletes from the 8 eligible matheletes in ____________ ways.

Combination = 56

A sandwich shop fills customer orders at a steady pace through the lunch hour, and averages 42 orders per lunch hour. To plan the number of employees to staff, the shop's manager needs to calculate both the expected value and variance of X = number of order in a five-minute period during lunch hour.

Expected Value = 42 x 5/60 = 3.5 orders per five minutes. The variance is the same as expected value for Poisson variables.

The sum of the probabilities of a list of mutually exclusive and exhaustive events is? - One - Impossible to determine without more information - One-half - Zero

One. 1. The probability of any event A is a value between 0 and 1 ; that is, 2. The sum of the probabilities of any list of mutually exclusive and exhaustive events equals 1.

Mike is placing a bet on an upcoming horse race in which seven horses are running. Mike places a trifecta bet that wins only if he correctly picks the first, second, and third place horses, in order. Mike can select the placing order for his bet in _____________ ways. Fill in blank.

Permutation Formula = 210

At a local restaurant, 20% of the customers order the chef's special. Suppose we define the binomial random variable X as the number of customers who order the chef's special if the restaurant anticipates 230 customers this evening, then the standard deviation for this binomial distribution is ___________. - 46.0 - 6.1 - 15.5 - 36.8

Standard deviation = sqrt (230 x 0.2 x 0.8) = 6.1