- Description
QNT 275 Week 5 Final Exam The 2016 Latest Version
| Results: | 26/29 (89.66%) |
***The questions of final exam are totally the same. Just the sequence is different.***
1
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?
45,100
54,900
-1.96
1.96
2
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 ___________.
None of the answers
negatively skewed
symmetric
positively skewed
3
Which of the following is a quantitative variable?
House age
All the answers
House price
House size
4
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 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.
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.
5
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 average temperature in Tampa, Florida, during the month of July
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
6
In the sample regression equation what is ?
The y-intercept
The predicted value of y, given a specific x value
The value of y when x = 0
The slope of the equation
7
Mutually exclusive events ______________.
do not share common outcomes
contain all possible outcomes
do not contain all possible outcomes
may share common outcomes
8
Which of the following can be represented by a discrete random variable?
The circumference of a randomly generated circle
The average distance achieved in a series of long jumps
The number of defective light bulbs in a sample of five
The time of a flight between Chicago and New York
9
A 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?
Provide the data sets to the restaurant owner for analysis by the owner’s staff.
Schedule staff based on the staffing levels used on the same date the prior year.
Perform descriptive statistics, inferential statistics, and time series analysis.
Create a graph of the data and extend the graph forward in time to set the schedule.
10
A-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 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.
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.
11
The two branches of the study of statistics are generally referred to as ___________.
differential and descriptive statistics
inferential and differential statistics
descriptive and referential statistics
descriptive and inferential statistics
12
Serial correlation is typically observed in:
time series data
outliers
sparse data
cross-sectional data
13
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?
Summarize the recommendations, supported by visual representation of the data and statistics.
Schedule a conference call with the owner and suppliers to discuss online ordering options.
Project the future online sales data using a line graph.
Provide the complete data set and all statistical analyses to the owner in spreadsheets.
14
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 84 percent
About 97.5 percent
About 95 percent
About 68 percent
15
Which of the following violates the assumptions of regression analysis?
The error term has a constant variance.
The error term is uncorrelated with an explanatory variable.
The error term has a zero mean.
The error term does not have the normal distribution.
16
The study of statistics can be defined as:
the language of data.
the art and science of getting information from data.
All of the answers
the study of collecting, analyzing, presenting, and interpreting data.
17
What is the name of the variable that’s used to predict another variable?
Coefficient of determination
Response
Explanatory
Standard error of the estimate
18
Consider a population with data values of 12, 8, 28, 22, 12, 30, 14.
The median is:
12
22
14
18
19
Which scales of data measurement are associated with quantitative data?
Nominal and ordinal
Ordinal and interval
Ratio and nominal
Interval and ratio
20
What is (are) the most widely used measure(s) of dispersion?
Covariance and the correlation coefficient
Interquartile range
Variance and standard deviation
Range
21
Frequency distributions may be used to describe which of the following types of data?
Nominal and interval data only
Nominal, ordinal, and interval data only
Nominal and ordinal data only
Nominal, ordinal, interval, and ratio data
22
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
Cross-sectional data
Time series data
Inferential statistics
23
What type of relationship is indicated in the scatterplot?
A negative linear relationship
A positive linear or curvilinear relationship
A negative curvilinear relationship
No relationship
24
Which of the following is most influenced by outliers?
75th percentile
Mean
Mode
Median
25
Bias can occur in sampling. Bias refers to _____________________.
the division of the population into overlapping groups
the creation of strata, which are proportional to the stratum’s size
the use of cluster sampling instead of stratified random sampling
the tendency of a sample statistic to systematically over-or underestimate a population parameter
26
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, median, and mode
Mean and median only
Mean only
27
The estimation of which of the following requires sampling?
The Cleveland Indians’ hitting percentage in 2010
The average SAT score of incoming freshmen at a university
U.S. unemployment rate
Total rainfall in Phoenix, Arizona, in 2010
28
Horizontal bar charts are constructed by placing:
each interval of values on the vertical axis and the appropriate range of values on the horizontal axis.
each category on the horizontal axis and the appropriate range of values on the vertical axis.
each category on the vertical axis and the appropriate range of values on the horizontal axis.
None of the Answers.
29
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%
1%
5%
2.5%