# QNT 275 FINAL EXAM (LATEST VERSION)

What is the name of the variable that's used to predict another variable?

Explanatory

Standard error of the estimate

Response

Coefficient of determination

Professors at a local university earn an average salary of $80,000 with a standard deviation of $6,000. 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

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

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.

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

Which of the following is most influenced by outliers?

Median

Mode

75th percentile

Mean

serial correlation is typically observed in:

sparse data

outliers

cross-sectional data

time series data

n 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

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

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.

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

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

The median is:

18

12

14

22

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

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

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

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.

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.

-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.

Which scales of data measurement are associated with quantitative data?

Interval and ratio

Nominal and ordinal

Ratio and nominal

Ordinal and interval

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

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.

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%

Mutually exclusive events ______________.

may share common outcomes

do not share common outcomes

contain all possible outcomes

do not contain all possible outcomes

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

Range

Covariance and the correlation coefficient

Variance and standard deviation

Interquartile range

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

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

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.

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

Which of the following is a quantitative variable?

House age

All the answers

House price

House size