61 Questions
| Total Attempts: 1541

Questions and Answers

- 1.AN event has probability 1.0. Which one of the following statements best describes this event in along sequence of trials?
- A.
This event is certain. It will definitely occur on every trial.

- B.
This event is extremely likely and will occur almost all the time.

- C.
This event is likely and will occur more often than not in the long run.

- D.
This event is likely; however it is more likely to NOT occur than to occur.

- E.
This event is very unlikely, but it will occur once in a while.

- 2.AN event has probability 0.95. Which one of the following statements best describes this event in along sequence of trials?
- A.
This event is certain. It will definitely occur on every trial.

- B.
This event is extremely likely and will occur almost all the time.

- C.
This event is likely and will occur more often than not in the long run.

- D.
This event is likely; however it is more likely to NOT occur than to occur.

- E.
This event is very unlikely, but it will occur once in a while.

- 3.AN event has probability 0.5. Which one of the following statements best describes this event in along sequence of trials?
- A.
This event is certain. It will definitely occur on every trial.

- B.
This event is extremely likely and will occur almost all the time.

- C.
This event is likely and will occur more often than not in the long run.

- D.
This event is likely; however it is more likely to NOT occur than to occur.

- E.
This event will occur half of the time in the long run

- 4.AN event has probability 0.35. Which one of the following statements best describes this event in along sequence of trials?
- A.
This event is certain. It will definitely occur on every trial.

- B.
This event is extremely likely and will occur almost all the time.

- C.
This event is likely and will occur more often than not in the long run.

- D.
This event is likely; however it is more likely to NOT occur than to occur.

- E.
This event will occur half of the time in the long run

- 5.AN event has probability 0.05. Which one of the following statements best describes this event in along sequence of trials?
- A.
This event is extremely likely and will occur almost all the time.

- B.
This event is likely and will occur more often than not in the long run.

- C.
This event is likely; however it is more likely to NOT occur than to occur.

- D.
This event is very unlikely, but it will occur once in a while.

- E.
This event is impossible. It can never occur.

- 6.AN event has probability 0.0. Which one of the following statements best describes this event in along sequence of trials?
- A.
This event is extremely likely and will occur almost all the time.

- B.
This event is likely and will occur more often than not in the long run.

- C.
This event is likely; however it is more likely to NOT occur than to occur.

- D.
This event is very unlikely, but it will occur once in a while.

- E.
This event is impossible. It can never occur.

- 7.
- A.
Standard deviation has a unit of measure.

- B.
Standard deviation is only positive.

- C.
Standard deviation is inflated by outliers.

- D.
Standard deviation should be used to measure spread even when the mean is not an appropriate measure of center.

- 8.A survey conducted by the Statistics Department to assess the study habits of the Stats221 students and obtained data from a sample of 1000 Stats221 students. The average number of hours per week studying for Stats221 class was found to be 15 with a standard deviation of 5. Is 15 a parameter or a statistic? Why?
- A.
A parameter because the average is for all Stats221 students.

- B.
A parameter because is the average for all Stats221 students at BYU.

- C.
A statistic because it summarizes the results of the entire population of Stats221 students at BYU.

- D.
A statistic because it summarizes the results of this sample of 1000 Stats221 students.

- 9.A survey conducted by the BYU-Salt Lake Center to assess the reasons students from BYU-Provo take classes at the Salt Lake Center instead of in Provo and obtained data from a sample of 1500 BYU-Provo students. The administration believes that BYU-Provo students take an average of 6 credits per semester at the BYU-SLC. The average number of credits taken by BYU-Provo students was found to be 11 with a standard deviation of 3. Is 6 a parameter or a statistic? Why?
- A.
A parameter because the average is for all students.

- B.
A parameter because it is the average for all students at BYU-Provo.

- C.
A statistic because it summarizes the results of the entire population of students at BYU-Provo.

- D.
A statistic because it summarizes the results of this sample of 1500 BYU-Provo students.

- 10.Which one of the following concepts says that if sample mean is based on a large simple random sample from a non-normal population, we can calculate approximate probabilities on sample mean using the standard Normal table?
- A.
The Law of Large Numbers.

- B.
The Central Limit Theorem.

- C.
The principle of least squares.

- D.
The sampling distribution of the mean.

- E.
There is no such result.

- 11.Theoretically, the "sampling distribution of sample mean" is which of the following?
- A.
The distribution of values of x in the population of interest.

- B.
The distribution of values of sample mean, but only in a very large samples.

- C.
The distribution of values of x in a specified sample from the population.

- D.
The distribution of values of sample mean from all possible samples of a specified size.

- E.
The histogram of values of x in a random sample of size n.

- 12.The price of a pound of grapes in the grocery stores along the Wasatch Front is distributed normally with a mean of $1.40 and a standard deviation of $0.15. A store selling a pound of grapes for $1.60 is considered expensive. What is the probability that a randomly selected store is selling expensive grapes?
- A.
0.9082

- B.
0.9099

- C.
0.0918

- D.
0.0901

- E.
0.1600

- 13.The price of a pound of grapes in the grocery stores along the Wasatch Front is distributed normally with a mean of $1.40 and a standard deviation of $0.15. What is the probability that the mean price of a pound of grapes of four randomly selected grocery stores will exceed $1.60?
- A.
0.0038

- B.
0.0918

- C.
0.9962

- D.
0.9082

- 14.What does Central Limit Theorem allow us to do?
- A.
Calculate probabilities of sample mean from a large random sample taken from a non-Normal population.

- B.
Determine whether the data are sampled from a population which is Normally distributed.

- C.
Specify the probability of obtaining each possible random sample of size n.

- D.
Know exactly what the value of the sample mean will be.

- 15.The histogram below represents the distribution of a population. Suppose a sampling distribution of is constructed from samples of size 60 from this population. Which one of the following figures best represents the sampling distribution?
- A.
A

- B.
B

- C.
C

- D.
D

- 16.The histogram below represents the distribution of a population. Suppose a sampling distribution of is constructed from samples of size 60 from this population. Which one of the following figures best represents the sampling distribution?
- A.
A

- B.
B

- C.
C

- D.
D

- 17.The histogram below represents the distribution of a population. Suppose a sampling distribution of is constructed from samples of size 60 from this population. Which one of the following figures best represents the sampling distribution?
- A.
A

- B.
B

- C.
C

- D.
D

- 18.Use the counts of the following table to answer the following questions:Which of the following is the conditional distribution for Professions for those whose ethnicity is Asian?
- A.
A

- B.
B

- C.
C

- D.
D

- 19.Use the counts of the following table to answer the following questions: What is the marginal percent of respondents who are lawyers?
- A.
18.18%

- B.
15.38%

- C.
42.86%

- D.
30%

- E.
27.08%

- 20.Use the counts of the following table to answer the following questions: Of the Asians, what percent are lawyers?
- A.
45.45%

- B.
18.18%

- C.
10.42%

- D.
81.81%

- 21.Use the counts of the following table to answer the following questions: Of the lawyers, what percent are Asians?
- A.
18.18%

- B.
15.38%

- C.
27.08%

- D.
30.76%

- 22.Consider the statement " The survey finds differences between Asians and Caucasians over professions. Just 7% of the Caucasians say that they are engineers; by contrast, more than 45% of the Asians say that they are engineers." Which of the following agrees with this statement:
- A.
There is a curved relationship between ethnicity and profession.

- B.
There is a linear relationship between ethnicity and profession.

- C.
There is an association between ethnicity and profession.

- D.
There is no association between ethnicity and profession.

- 23.Students who have taken Stats221 were asked in a survey about their Stats221 Final exam scores and how much time they spent studying for the class.The correlation coefficient between these two variables is 0.90. On the basis of this information, approximately what percentage of the variation in Stats221 Final exam score can be explained by how time students spent studying for the class?
- A.
90%

- B.
9%

- C.
81%

- D.
None of the above

- 24.Consider these plots: the plot on the left is a scatterplot and the plot on the right is the corresponding residual plot from fitting a regression line. On the basis of these plots, is fitting the data with least-squares regression appropriate? Why or why not?
- A.
No, because the relationship between X and Y is non-linear.

- B.
No, because Y has more spread for larger value of X.

- C.
No, because there is no relationship between X and Y.

- D.
Yes, because X and Y has a linear relationship.

- E.
Yes, because there is a relationship between X and Y.

- 25.Consider these plots: the plot on the left is a scatterplot and the plot on the right is the corresponding residual plot from fitting a regression line. On the basis of these plots, is fitting the data with least-squares regression appropriate? Why or why not?
- A.
No, because the relationship between X and Y is non-linear.

- B.
No, because Y has more spread for larger value of X.

- C.
No, because there is no relationship between X and Y.

- D.
Yes, because X and Y has a linear relationship.

- E.
Yes, because there is a relationship between X and Y.