ECON 2030 Exam 1 Questions

The correlation coefficient Select one: a. is the same as the covariance b. can be larger than 1 c. cannot be larger than 1 d. cannot be negative

C. cannot be larger than 1

During lunchtime, customers arrive at Bob's Drugs according to a Poisson distribution with on average 4 customers per minute. During a one minute interval, determine the following probability: no arrivals

0.018

AMR is a computer-consulting firm. The number of new clients that they have obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below. Number of New Clients Probability 0 0.05 1 0.10 2 0.15 3 0.35 4 0.20 5 0.10 6 0.05 The expected number of new clients per month is Select one: a. 6 b. 0 c. 3.05 d. 21

C. 3.05

The median of a sample will always equal the Select one: a. mode b. mean c. 50th percentile d. all of these answers are correct

C. 50th percentile

During lunchtime, customers arrive at Bob's Drugs according to a Poisson distribution with on average 4 customers per minute. During a one minute interval, determine the following probability: three or more arrivals. Select one: a. .762 b. .689 c. .147 d. .733

A. .762

During lunchtime, customers arrive at Bob's Drugs according to a Poisson distribution with on average 4 customers per minute. What is the probability of two arrivals in a two-minute period? Select one: a. 0.011 b. 0.018 c. 0.016 d. 0.07

A. 0.011

A life insurance company has determined that the number of claims filed follows a Poisson distribution in its Nashville branch. On average, seven claims are filed per week. What is the probability that during the next week fewer than four claims will be filed? Select one: a. 0.082 b. 0.022 c. 0.052 d. 0.091

A. 0.082

AMR is a computer-consulting firm. The number of new clients that they have obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below. Number of New Clients Probability 0 0.05 1 0.10 2 0.15 3 0.35 4 0.20 5 0.10 6 0.05 The standard deviation is Select one: a. 1.431 b. 2.047 c. 3.05 d. 21

A. 1.431

A researcher has collected the following sample data. 5 12 6 8 5 6 7 5 12 4 The sample variance is Select one: a. 8.22 b. 9.12 c. 6.20 d. 5

A. 8.22

Employee Number is an example of ________ data. Select one: a. nominal b. ordinal c. interval d. ratio

A. Nominal

Gender is an example of ________ data. Select one: a. nominal b. ordinal c. interval d. ratio

A. Nominal

If we only have the relative frequency table for the outcomes of a discrete random variable, Excel's __________ function can be used to compute the expected value of this discrete random variable. Select one: a. SUMPRODUCT b. AVERAGE c. MEDIAN d. VAR

A. SUMPRODUCT

The probability distribution for the daily sales at Michael's Co. is given below. Daily Sales ($1,000s) Probability 40 0.1 50 0.4 60 0.3 70 0.2 The expected daily sales are Select one: a. $55,000 b. $56,000 c. $50,000 d. $70,000

B. $56,000

The probability that Pete will catch fish on a particular day when he goes fishing is 0.8. Pete is going fishing 3 days next week. The probability that Pete will catch fish on exactly one day is Select one: a. .008 b. .096 c. .104 d. .8

B. .096

The probability that Pete will catch fish on a particular day when he goes fishing is 0.8. Pete is going fishing 3 days next week. The variance of the number of days Pete will catch fish is Select one: a. .16 b. .48 c. .8 d. 2.4

B. .48

AMR is a computer-consulting firm. The number of new clients that they have obtained each month has ranged from 0 to 6. The number of new clients has the probability distribution that is shown below. Number of New Clients Probability 0 0.05 1 0.10 2 0.15 3 0.35 4 0.20 5 0.10 6 0.05 The variance is Select one: a. 1.431 b. 2.0475 c. 3.05 d. 21

B. 2.0475

A researcher has collected the following sample data. The mean of the sample is 5. 3 5 12 3 2 The coefficient of variation is Select one: a. 72.66% b. 81.24% c. 264% d. 330%

B. 81.24%

When using Excel's BINOM.DIST function, one should choose TRUE for the fourth input if Select one: a. a probability is desired b. a cumulative probability is desired c. the expected value is desired d. the correct answer is desired

B. A cumulative probability is desired

After the data has been arranged from smallest value to largest value, the value in the middle is called the Select one: a. range b. median c. mean d. None of the other answers are correct.

B. Median

During a cold winter, the temperature stayed below zero for ten days (ranging from -20 to -5). The variance of the temperatures of the ten day period Select one: a. is negative since all the numbers are negative b. must be at least zero c. can not be computed since all the numbers are negative d. can be either negative or positive

B. Must be at least zero

A discrete probability distribution for which the relative frequency method is used to assign probabilities is the​ Select one: a. ​binomial distribution b. ​empirical discrete distribution c. ​hypergeometric distribution d. ​discrete uniform distribution

B. empirical discrete distribution

A researcher has collected the following sample data. 5 12 6 8 5 6 7 5 12 4 What is the residual of the observation "4"? Select one: a. 3 b. 4 c. -3 d. -1

C. -3

The probability that Pete will catch fish on a particular day when he goes fishing is 0.8. Pete is going fishing 3 days next week. The probability that Pete will catch fish on one day or less is Select one: a. .008 b. .096 c. .104 d. .8

C. .104

A researcher has collected the following sample data. The mean of the sample is 5. 3 5 12 3 2 The range is Select one: a. 1 b. 2 c. 10 d. 12

C. 10

The probability that Pete will catch fish on a particular day when he goes fishing is 0.8. Pete is going fishing 3 days next week. The expected number of days Pete will catch fish is Select one: a. .6 b. .8 c. 2.4 d. 3

C. 2.4

A population is a. the same as a sample b. the selection of a random sample c. the collection of all items of interest in a particular study d. always the same size as the sample

C. The collection of all items of interest in a particular study

Which of the following is a characteristic of a binomial experiment? Select one: a. at least 2 outcomes are possible b. the probability of success changes from trial to trial c. the trials are independent d. All of these answers are correct.

C. The trials are independent

A random variable that can assume only a finite number of values is referred to as a Select one: a. infinite sequence b. finite sequence c. discrete random variable d. discrete probability function

C. discrete random variable

Which of the following is not a characteristic of an experiment where the binomial probability distribution is applicable? Select one: a. the experiment has a sequence of n identical trials b. exactly two outcomes are possible on each trial c. the trials are dependent d. the probabilities of the outcomes do not change from one trial to another

C. the trials are dependent

Which of the following is NOT a required condition for a discrete probability function? Select one: a. f(x) ≥ 0 for all values of x b. ∑f(x) = 1 c. ∑f(x) = 0 d. All of the answers are correct.

C. ∑f(x) = 0

A life insurance company has determined that the number of claims filed follows a Poisson diA life insurance company has determined that the number of claims filed follows a Poisson distribution in its Nashville branch. On average, seven claims are filed per week. What is the probability that during the next week exactly seven claims will be filed?

.149

A manufacturer of computer disk drives has a historical defective rate of .001. What is the probability that in a batch of 1000 drives, 2 would be defective?

0.184

A life insurance company has determined that the number of claims filed follows a Poisson distribution in its Nashville branch. On average, seven claims are filed per week. What is the probability that during the next week at least seventeen claims will be filed? Select one: a. 0.999 b. 0.002 c. 0.998 d. 0.001

D. 0.001

A life insurance company has determined that the number of claims filed follows a Poisson distribution in its Nashville branch. On average, seven claims are filed per week. What is the probability that during the next week there are either 4 or 5 claims will be filed? Select one: a. 0.091 b. 0.128 c. 0.149 d. 0.219

D. 0.219

x is a random variable with the probability function: f(x) = x/6 for x = 1,2 or 3. The expected value of x is Select one: a. 0.333 b. 0.500 c. 2.000 d. 2.333

D. 2.333

In many universities, students evaluate their professors by means of answering a questionnaire. Assume a questionnaire is distributed to a class of 45 students. Students are asked to answer the following: 1. Sex 2. Race (Black, White, Other) 3. Age 4. Number of hours completed 5. Grade point average 6. My instructor is a very effective teacher 1 2 3 4 5 strongly agree moderately agree neutral moderately disagree strongly disagree Refer to Exhibit 1-4. How many variables are in this data set? Select one: a. 3 b. 4 c. 5 d. 6

D. 6

A researcher has collected the following sample data. 5 12 6 8 5 6 7 5 12 4 The 75th percentile is: Select one: a. 5 b. 6 c. 7 d. 8

D. 8

The empirical rule states that, for data having a bell-shaped distribution, the percentage of data values being within two standard deviations of the mean is approximately​ Select one: a. ​65 b. ​75 c. ​85 d. ​95

D. 95

Excel's BINOM.DIST function can be used to compute Select one: a. bin width for histograms b. binomial probabilities c. cumulative binomial probabilities d. Both binomial probabilities and cumulative binomial probabilities are correct.

D. Both binomial probabilities and cumulative binomial probabilities are correct.

As one of its major contributions, statistics uses data from a sample to make estimates and test hypotheses about the characteristics of a population through a process referred to as Select one: a. hypothesis of the sample b. descriptive statistics c. influencing the sample information d. statistical inference

D. Statistical inference