OBA 311 HW1

If A and B are independent events with P(A) = 0.4 and P(B) = 0.6, then P(A intersect B) = a. 0.76. b. 1.00. c. 0.24. d. 0.20.

.4 * .6 = .24 or c

A company plans to interview 10 recent graduates for possible employment. The company has three positions open. How many groups of three can the company select?

10!/ (10-3)! 3!=10! / 7! = 120 ways

A trader who wants to predict short-term movements in stock prices is likely to use ( ) analytics. A) predictive B) descriptive C) normative D) prescriptive

A

Which of the following allow meaningful comparison of ranges, averages and other statistics? A) interval data B) categorical data C) ratio data D) ordinal data

A

Which of the following is a disadvantage of ordinal data? A) They bear no relationship to one another. B) They have no fixed units of measurement. C) They have no natural zero. D) They are not comparable with each other.

B

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? A) prescriptive analytics B) normative analytics C) descriptive analytics D) predictive analytics

C

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

C

Which of the following is an example of a measure of continuous metrics? A) four errors revealed in an invoice B) a delivery delayed by seven days C) weight and volume of a sheet of steel D) three incomplete orders on a day

C

Nominal data: A) are ranked according to some relationship to one another. B) have constant differences between observations. C) are continuous and have a natural zero. D) are sorted into categories according to specified characteristics.

D

Predictive analytics: A) summarizes data into meaningful charts and reports that can be standardized or customized. B) identifies the best alternatives to minimize or maximize an objective. C) uses data to determine a course of action to be executed in a given situation. D) detects patterns in historical data and extrapolates them forward in time.

D

A deterministic model is one in which all model input information is either known or assumed to be known with certainty. T/F

True

in R, getwd( ) is used to check working directory. T/F

True

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 a. counting rule for permutations. b. counting rule for combinations. c. counting rule for independent events. d. counting rule for multiple-step random experiments.

a

µ is an example of a a. population parameter. b. sample statistic. c. population variance. d. mode.

a

In an experiment, events A and B are mutually exclusive. If P(A) = 0.6, then the probability of B a. cannot be larger than 0.4. b. can be any value greater than 0.6. c. can be any value between 0 to 1. d. cannot be determined with the information given.

a since 1-0.6=0.4

Six applications for admission to a local university are checked, and it is determined whether each applicant is male or female. How many sample points exist in the above experiment? a. 64 b. 32 c. 16 d. 4

a since 2^6=64

An experiment consists of tossing 4 coins successively. The number of sample points in this experiment is a. 16. b. 8. c. 4. d. 2. e. none

a since 4^2=16

When n-1 is used in the denominator to compute variance, a. the data set is a sample. b. the data set is a population. c. the data set could be either a sample or a population. d. the data set is from a census.

a. since If the variance has n-1 in the formula, it means that the set is a sample. We try to estimate the population variance by dividing the sum of squared difference with the mean with n-1. When we have the actual population data we can directly divide the sum of squared differences with n instead of n-1.

Any process that generates well-defined outcomes is a. an event. b. an experiment. c. a sample point. d. a sample space.

b

Each individual outcome of an experiment is called a. the sample space. b. a sample point. c. a trial. d. an event.

b

Two events are mutually exclusive a. if their intersection is 1. b. if they have no sample points in common. c. if their intersection is 0.5. d. if most of their sample points are in common.

b

Weddings Couple's Income : $130,000, $157,000 Bride's age: 22, 23 Payor: Bride's Parents, Bride's Parents Wedding cost: $60,700.00, $52,000.00 Attendance: 300, 350 Value Rating: 3, 1 Wedding cost is ( ) data type. a. categorial b. ratio c. ordinal d. interval

b

f P(A) = 0.7, P(B) = 0.6, P(A intersect B) = 0, then events A and B are a. non-mutually exclusive. b. mutually exclusive. c. independent events. d. complements of each other.

b

If P(A) = 0.58, P(B) = 0.44, and P(A intersect B) = 0.25, then P(A union B) = a. 1.02. b. 0.77. c. 0.11. d. 0.39.

b since 0.58+0.44-0.25=0.77

A researcher has collected the following sample data. The mean of the sample is 5. 3 5 12 3 2 The standard deviation is a. 8.944. b. 4.062. c. 13.2. d. 16.5.

b since s^2=16.5 and square root of 16.5 is 4.062

If A and B are independent events with P(A) = 0.4 and P(B) = 0.25, then P(A union B) = a. 0.65. b. 0.55. c. 0.10. d. 0.75.

b. since P(A and B)=0.4x0.25=0.1 so 0.4+0.25-0.1=0.55

An unusually small or unusually large data value is called a. correlation coefficient. b. a deviation. c. an outlier. d. a variable.

c

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)

c

Events that have no sample points in common are a. independent events. b. posterior events. c. mutually exclusive events. d. complements.

c

If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P(A intersect B) = a. 0.30. b. 0.15. c. 0.00. d. 0.20.

c

If a six sided die is tossed two times and "3" shows up both times, the probability of "3" on the third trial is a. much larger than any other outcome. b. much smaller than any other outcome. c. 1/6. d. 1/216.

c

The 75th percentile is referred to as the a. first quartile. b. second quartile. c. third quartile. d. fourth quartile.

c

The intersection of two mutually exclusive events a. can be any value between 0 to1. b. must always be equal to 1. c. must always be equal to 0. d. can be any positive value. e. none

c

The median of a sample will always equal the a. (Q1 + Q3)/2. b. Q4/2. c. 50th percentile. d. (smallest value + largest value)/2.

c

The range of probability is a. 0 to infinity. b. minus infinity to plus infinity. c. 0 to 1. d. -1 to 1.

c

The sample space refers to a. any particular experimental outcome. b. the sample size minus one. c. the set of all possible experimental outcomes. d. an event.

c

The union of events A and B is the event containing all the sample points belonging to a. B or A. b. A or B. c. A or B or both. d. A or B, but not both.

c

An experiment consists of three steps. There are four possible results on the first step, three possible results on the second step, and two possible results on the third step. The total number of experimental outcomes is a. 9. b. 14. c. 24. d. 36.

c since 4x3x2=24

If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P(A union B) = a. 0.00. b. 0.15. c. 0.80. d. 0.20.

c since P(A)+P(B)=0.8

If P(A) = 0.50, P(B) = 0.40 and P(A union B) = 0.88, then P(B |A) = a. 0.02. b. 0.03. c. 0.04. d. 0.05.

c since P(AandB)= 0.5+0.4-0.88=0.02 so P(B|A)=0.02/0.5=0.04

Growth factors for the population of Chattanooga in the past two years have been 8 and 12. The geometric mean has a value of a. 20 b. square root 20 c. square root 96 d. 96

c since square root 8*12=square root 96

If two events are independent, then a. they must be mutually exclusive. b. the sum of their probabilities must be equal to one. c. their intersection must be zero. d. the product of their probabilities gives their intersection.

d

The sum of the probabilities of two complementary events is a. 0. b. 0.5. c. 0.57. d. 1.0.

d

The geometric mean of 2, 4, 8 is a. 4.67. b. 5.0. c. 16. d. 4.0.

d since (log2+log4+log8)/3=0.60206 andAntilog 0.60206=4

Assume your favorite soccer team has 2 games left to finish the season. The outcome of each game can be win, lose or tie. The number of possible outcomes is a. 2. b. 4. c. 6. d. 9.

d since 3^2=9

A group of students had dinner at a local restaurant. The total bill for the dinner was $414.70. Each student paid his/her equal share of the bill, which was $18.85. How many student's were at the dinner? a. 4 b. 415 c. 19 d. 22

d since 414.7/18.85=22

If X and Y are mutually exclusive events with P(A) = 0.295, P(B) = 0.32, then P(A | B) = a. 0.0944. b. 0.6150. c. 1.0000. d. 0.0000.

d since P(A|B)=P A and B/PB= 0/0.32=0

If A and B are independent events with P(A) = 0.2 and P(B) = 0.6, then P(A U B) = a. 0.62. b. 0.12. c. 0.60. d. 0.68.

d. since P(A and B)= 0.2*0.6=0.12 so 0.2+0.6-0.12=0.68

If P(A) = 0.62, P(B) = 0.47, and P(A union B) = 0.88, then P(A intersect B) = a. 0.2914. b. 1.9700. c. 0.6700. d. 0.2100.

d. since...0.88 = 0.62 + 0.47 - P(A n B) P(A n B) = 0.62 + 0.47 - 0.88 P(A n B) = 0.21

In R: To get help with mean function, you can use

help(mean)