QNT 275 Final Exam/ QNT 275 Final Exam New 2016 (All are correct)

1. What is the name of the variable that’s used to predict another variable? 

​Explanatory

​Standard error of the estimate

​Response

​Coefficient of determination
​2. Professors at a local university earn an average salary of $80000 with a standard deviation of $6000. The salary distribution is approximately bell-shaped. What can be said about the percentage of salaries that are at least $74,000? 

​About 97.5 percent

​About 84 percent

​About 68 percent

​About 95 percent

3. What type of relationship is indicated in the scatterplot? 

​A positive linear or curvilinear relationship

​No relationship

​A negative curvilinear relationship

​A negative linear relationship

4. The study of statistics can be defined as:

​the art and science of getting information from data.

​All of the answers

​the language of data.

​the study of collecting, analyzing, presenting, and interpreting data.

 ​5. In the accompanying stem-and-leaf diagram the values in the stem and leaf portions represent 10s and 1s digits, respectively. The stem-and-leaf diagram shows that the distribution is ___________. 

​​symmetric

​positively skewed

​negatively skewed

​None of the answers

6. Which of the following is most influenced by outliers?  

​Median

​Mode

​75th percentile

​Mean

7. Serial correlation is typically observed in: 

​sparse data

​outliers

​cross-sectional data

​time series data

8. In the sample regression equation  what is  ? 

​The value of y when x = 0

​The predicted value of y, given a specific x value

​The slope of the equation

​The y-intercept

 9. Bias can occur in sampling Bias refers to _____________________. 

​the use of cluster sampling instead of stratified random sampling

​the division of the population into overlapping groups

​the tendency of a sample statistic to systematically over-or underestimate a population parameter

​the creation of strata, which are proportional to the stratum’s size

10. The manager of a retail shoe store has applied statistics to analyze sales purchasing, and  data and reached the conclusion that the store could reduce costs by reducing inventory of very small and very large sizes, and substituting an online ordering service to drop-ship rare sizes directly from suppliers. How should the manager communicate those results to the store owner? 

​Provide the complete data set and all statistical analyses to the owner in spreadsheets.

​Schedule a conference call with the owner and suppliers to discuss online ordering options.

​Project the future online sales data using a line graph.

​Summarize the recommendations, supported by visual representation of the data and statistics.

11. Which of the following can be represented by a continuous random variable?

​The number of typos found on a randomly selected page of this test bank

​The number of customers who visit a department store between 10:00 a.m. and 11:00 a.m. on Mondays

​The number of students who will get financial assistance in a group of 50 randomly selected students

​The average temperature in Tampa, Florida, during the month of July

12. Consider a population with data values of 12, 8, 28, 22, 12, 30, 14.

The median is:

​18

​12

​14

​22

 13. The salaries of teachers in a particular school district are normally distributed with a mean of $50,000 and a standard deviation of $2,500. Due to budget limitations, it has been decided that the teachers who are in the top 2.5% of the salaries would not get a raise. What is the salary level that divides the teachers into one group that gets a raise and one that doesn’t? 

​-1.96

​54,900

​1.96

45,100​

14. The two branches of the study of statistics are generally referred to as ___________. 

​descriptive and referential statistics

​inferential and differential statistics

​differential and descriptive statistics

​descriptive and inferential statistics

15. The estimation of which of the following requires sampling? 

​U.S. unemployment rate

​The Cleveland Indians’ hitting percentage in 2010

​The average SAT score of incoming freshmen at a university

​Total rainfall in Phoenix, Arizona, in 2010

16. Which of the following meets the requirements of a stratified random sample?

​A population contains 10 members under the age of 25 and 20 members over the age of 25. The sample will include six people chosen at random, without regard to age.

​A population contains 10 members under the age of 25 and 20 members over the age of 25. The sample will include two people chosen at random under the age of 25 and four people chosen at random over 25.

​A population contains 10 members under the age of 25 and 20 members over the age of 25. The sample will include six males chosen at random, without regard to age.

​A population contains 10 members under the age of 25 and 20 members over the age of 25. The sample will include six people who volunteer for the sample.

17. Manager of a fast food restaurant wants to ensure that staff are scheduled with the sufficient hours required to meet customer demands without overspending on labor costs. The manager has daily guest counts, sales data, and staff hours for the prior year. What should the manager do next in order to reach conclusions about scheduling restaurant staff? 

​Perform descriptive statistics, inferential statistics, and time series analysis.

​Schedule staff based on the staffing levels used on the same date the prior year.

​Provide the data sets to the restaurant owner for analysis by the owner’s staff.

​Create a graph of the data and extend the graph forward in time to set the schedule.

18. -Plus Dry Cleaners wants to understand its customers’ perceptions of the quality of the company’s customer service. They plan to survey a sample of its customer base. What will A-Plus need to do to ensure that their data is valid and reliable? 

​The survey must include items that ask customers to rate the appearance of the dry cleaning store, the survey must include all customers, and the survey method must include setting up a table outside the local dollar store.

​The survey must include items that ask customers about their dry cleaning experiences, the survey sample must include the first 15 customers off the customer database, and the survey method must be repeatable.

​The survey must include items that ask customers to rate the quality of the company’s customer service, the survey sample must represent all parts of the customer population, and the survey method must be repeatable.

​The survey must include items that ask customers to rate the friendliness of the staff, the survey must include all customers from the north side of the city, and the survey method must appeal to all respondents.

19. Which scales of data measurement are associated with quantitative data?  

​Interval and ratio

​Nominal and ordinal

​Ratio and nominal

​Ordinal and interval

 20. ​The owner of a company has recently decided to raise the salary of one employee, who was already making the highest salary, by 20%. Which of the following is(are) expected to be affected by this raise?

​Median only

​Mean only

​Mean and median only

​Mean, median, and mode
​21. Which of the following violates the assumptions of regression analysis?

​The error term does not have the normal distribution.

​The error term is uncorrelated with an explanatory variable.

​The error term has a constant variance.

​The error term has a zero mean.

22. A hedge fund returns on average 26% per year with a standard deviation of 12%. Using the empirical rule, approximate the probability the fund returns over 50% next year.

​0.5%

​2.5%

​1%

​5%

23. Mutually exclusive events ______________. 

​may share common outcomes

​do not share common outcomes

​contain all possible outcomes

​do not contain all possible outcomes

24. What is (are) the most widely used measure(s) of dispersion? 

​Range

​Covariance and the correlation coefficient

​Variance and standard deviation

​Interquartile range
​25. Frequency distributions may be used to describe which of the following types of data?  

​Nominal and interval data only

​Nominal, ordinal, interval, and ratio data

​Nominal, ordinal, and interval data only

​Nominal and ordinal data only
​26. A company wants to estimate the mean price of oil over the past 10 years. What kind of data does the company need?

​Descriptive statistics

​Inferential statistics

​Time series data

​Cross-sectional data
​27. Horizontal bar charts are constructed by placing: 

​each category on the horizontal axis and the appropriate range of values on the vertical axis.

​None of the Answers.

​each category on the vertical axis and the appropriate range of values on the horizontal axis.

​each interval of values on the vertical axis and the appropriate range of values on the horizontal axis.

28. Which of the following can be represented by a discrete random variable? 

​The time of a flight between Chicago and New York

​The average distance achieved in a series of long jumps

​The number of defective light bulbs in a sample of five

​The circumference of a randomly generated circle

29. Which of the following is a quantitative variable?  

​House age

​All the answers

​House price

​House size