Business Statistics MidTerm
the coefficient of variation is best described as .......
a relative measure of dispersion
one of the primary goals when constructing a frequency distribution for quantitive data is to summarize the data in a manner that.....
accurately depicts the data as a whole
northern university wants to determine the average starting salary for last year's graduates of its College of Business. What is the population from which the survey is taken?
all of last year's graduates from Northern's College of Business who started working
the interval scale of measurement ....
allows for the use of negative values
stem & leaf diagrams can be used to
analyze the shape of the data determine how dispersed the data are observe individual data points
we can compute only ____________ answers for the mean and variance
approximate
a _______ depicts the frequency or the relative frequency for each category of a qualitative variable as a series of horizontal or vertical bars, the lengths of which are proportional to the values that are to be depicted.
bar chart
examples of mutually exclusive events
being on time and being late for an appointment receiving an A and receiving a B as a final grade in an accounting class
with nominal data, you can ...
categorize the data
the __________ formula is used to determine the number of different ways to arrange a group of x objects from a total of n objects when the order of the objects is irrelevant.
combination
a useful way to summarize data that has to do with comparing cost (high,avg,low) versus the quality of ranking the hotel (excellent, good,fair,poor) is to construct a ________.
contingency table
the numerical measure that reveals only the direction of the linear relationship between 2 variables, but not the strength of the linear relationship, is referred to as the _________.
covariance
data that are collected about many subjects as the same point in time or without regard to differences in time are known as ___________ data.
cross-sectional
when a researcher examines quantitative data and wants to know the number of observations that fall below the upper limit of a particular class, the researcher is best served by creating a _________.
cumulative frequency distribution
The branch of statistics that summarizes important aspects of a data set is often referred to as __________________ statistics.
descriptive
Using the multiplication rule, the probability that event A and event B both occur is computed by multiplying the conditional probability of event A given event B by the probability of ______________.
event B
events that include all outcomes in the sample space are known as __________ events
exhaustive
in a data set, the value 50 is the 25th percentile, or equivalently, the _________.
first quartile
a __________ is a way to organize qualitative data into categories and record the number of observations in each category
frequency distribution
the probability of randomly selecting a spade from a deck of cards is
.25 (52/4 then 13/52)
let P(A) = .30 and P(B)=40. suppose that A and B are independent events. calculate P(A|B).
.30 since P(A|B) = P(A)
contingency tables are useful to analyze ....
2 categorical variables
A new dining plan was implemented in a residence hall at State University. Residents were asked to assess the new plan and give a grade of A, B, C, D, or F to the new dining plan. Of 480 residents, 234 gave a grade of B, 85 a grade of C, 13 a grade of D, and 4 a grade of F. The number if A grades is _______.
480-234-85-13-4 = 144
which of the following is an example of descriptive statistics? A. estimate the percent of all US voters who approve of the president's performance B. calculate the percent of 2500 US voters in an opinion poll who approves of the president's performance C. test whether the average lifetime of all brand A batteries exceeds 500 hours based on lifetime data from a sample of 20 Brand A batteries D. Conclude which of two brands of coffee is preferred by all coffee consumers based on taste-test preferences of 200 coffee drinkers
B. calculate the percent of 2500 US voters in an opinion poll who approves of the president's performance
all of the following are examples of continuous variables EXCEPT A. the weight of a newborn baby B. the number of children in a family C. the height of a 13 year old boy D. the time it takes a student to complete an exam
B. the number of children in a family
Samples are primarily used to A. define a population B. contradict the population data C. make inferences about population parameters
C. make inferences about population parameters
all of the following are examples of cross-sectional data EXCEPT: A. last month's unemployment rate for various cities in Ohio B. last year's starting salary for 100 recent business graduates at Penn State University C. quarterly sales for a computer company for the last 5 years D. the hours worked last week by 50 employees at a factory
C. quarterly sales for a computer company for the last 5 years
which of the following is an example of inferential statistics? A. find the average height of 50 female students at State University B. calculate a mutual fund's average return for the last 5 years C. test the longevity of all light bulbs based on a sample of 100 light bulbs D. summarize the variability of the exam scores of 40 students based on all 40 exam scores
C. test the longevity of all light bulbs based on a sample of 100 light bulbs
From the scenarios below, indicate the one that best reflects the nominal scale A. rank the service at a restaurant on a scale of 1 to 4. B. calculate the time it takes a worker to package a product for shipment C. note the ages of students in an undergraduate classroom D. designate males as 0 and females as 1 to compare gender performance on an aptitude test
D. designate males as 0 and females as 1 to compare gender performance on an aptitude test
which of the following is an example of cross-sectional data? A. GDP of the United States from 1990-2010 B. quarterly housing starts collected over the last 60 years C. daily price of DuPont stock during the first quarter D. results of market research testing current consume preferences for soda drinks
D. results of market research testing current consume preferences for soda drinks (key word = current)
for 2 events A and B, the multiplication rule is
P(AnB) = P(A|B)*P(B)
the ______________ is used to analyze multi-year investments because it more accurately measures returns over time.
geometric mean
when calculating average growth rates, we apply the formula for the ________.
geometric mean
in descriptive statistics, a polygon is best described as a ........
graph that connects the midpoints of each class and its associated frequency or relative frequency
the probability that a customer will purchase a product is .15. the probability that a customer is a male is .5. the probability that a customer is a male and will purchase a product is .075. The events purchasing a product and being a male are-___________.
independent (P(A)*P(B)=0.15*.5=.075 = P(AnB))
a stem-and-leaf diagram has 2 parts: the stem and the leaf. The stem consists of the _________ and the leaf consists of the ________.
leftmost digits; last digit
generally, the ________ is the best measure of central location when outliers are present.
median
which values are included in a box plot?
median 25th percentile 50th percentile 75th percentile
A professor's gender (male, female) represents _______________ data and a professor's rank (assistant, associate, full) represent ________________ data.
nominal, ordinal
In general, we use sample data because
obtaining data from the population is often an expensive process
How does an ogive differ from a polygon?
ogive = cumulative (relative) frequency polygon = (relative) frequency distribution
MAD is denominated in the same units as the ________________.
original data
One method of graphical presentation for qualitative data is a ________
pie chart
an _________ is a segmented circle whose segments portray the relative frequencies of the categories of some qualitative variable .
pie chart
a ________ includes all items of interest in a statistical problem
population
a __________ includes all items of interest in a statistical problem
population
a relative frequency distribution for quantitative data identifies the ....
proportion of observations that occur in each class
a bar chart is a useful graphical tool for ____________ data
qualitative
consider a following variable: the color of a car in a parking lot. This variable is best categorized as a ___________ variable.
qualitative
when constructing a histogram, what values/ labels go on the horizontal (x) axis and the vertical (y) axes?
quantitative class limits on the horizontal axis; frequency or relative frequency on the vertical axis
the _______ measures the differences between the largest and smallest values in a data
range
a research analyst collects data on the weekly closing price of gold throughout the year. The scale for these data is ...
ratio
mean-variance analysis uses risk and reward to evaluate the rate of return of an asset. How are the risk and reward measured?
risk = variance reward = mean
the notation s^2 represents the ________.
sample variance
Sampling, rather than surveying an entire population, can offer some substantial benefits. Some of those benefits include
saving money & time
which of the following graphical depictions are useful to observe the shape (distribution) of a data set for a single variable ?
stem & leaf diagram polygon histogram
a softball coach believes that Laurie has a .5 probability of getting a hit against a particular pitcher that Laurie has never batted against before. this type of probability is best categorized as an ___________________ probability.
subjective
when constructing classes for a frequency distribution for quantitative data, what is true?
the classes should be exhaustive the classes should be mutually exclusive in general, the classes should be the same width
which of the following characteristic of interest is a variable?
the number of pizzas ordered from Pizza Hut per day (key word = per day)
what is an example of the interval scale?
the outside temperature (in degrees Fahrenheit)
if 2 events are independent, then the probability that both events occur equals ........
the product of the individual probabilities
data that are collected by recording a characteristic of a subject over several time periods are referred to as _________ data.
time series
Statistics is used
to make informed decisions based on data
An ogive is a graph that plots the cumulative frequency, or cumulative relative frequency, against the......
upper limit of the corresponding class
a characteristic of interest that differs among various observations is referred to as a ________
variable
When a mean is calculated and some observations are given greater importance or value, we refer to this measure of central location as a ______.
weighted mean
Chebyshev's Theorem is applicable......
when the data have any shape
