Exam 1

When examining a distribution of a quantitative variable, which of the following features do we look for?

-Overall shape, center, and spread -Symmetry or skewness -Deviations from overall patterns such as outliers -The number of peaks or modes

The appearance of a histogram will change when you _______.

-change the class size -add more data -remove outliers

When using a pie chart, the sum of all the percentages should be _____.

100

The first day of class the professor collects information on each student to make a data set that will be analyzed throughout the semester. The information asked includes hometown, GPA, number of classes, number of siblings, and favorite subject. How many variables are in this data set?

5

Jason is buying a new computer. He is comparing various models using many different variables. These variables play an important role in making the decision about which computer he will buy. Identify each of the following variables as categorical or quantitative. A)Does the computer come with a USB port? B)What is the hard drive size of the computer? C)Is the computer a laptop or a desktop model? D)How much does the computer cost?

A) Categorical B) Quantitative C) Categorical D) Quantitative

A study is conducted on students taking a statistics class. Several variables are recorded in the survey. Identify each variable as categorical or quantitative. A)The type of car the student owns B)The number of credit hours taken during that semester C)The time the student waited in line at the bookstore to pay for his/her textbooks D)The home state of the student

A) Categorical B) Quantitative C) Quantitative D) Categorical

Researchers are conducting a state-wide survey for the U.S. Postal Service. The survey records many different variables of interest. Which of the following variables is categorical? A)The county of residence B)The number of people, both adults and children, living in the household C)The total household income, before taxes, in 2010 D)The age of the respondent

A) The country of residence

A particularly common question in the study of wildlife behavior involves observing contests between "residents" of a particular area and "intruders." In each contest, the residents either win or lose the encounter (assuming there are no ties).Observers might record several variables, some of which are listed below. Which of these variables is categorical? A)The duration of the contest (in seconds) B)The number of animals involved in the contest C)Whether the residents win or lose D)The total number of contests won by the residents

C)Whether the residents win or lose

A description of different houses on the market includes the following three variables. Which of these variables is quantitative? A)The square footage of the house B)The monthly gas bill C)The monthly electric bill D)All of the above

D) All of the above

(T/F)When using a histogram to display categorical values, you should make sure the categories are in alphabetical order.

False—You cannot use histograms to display categorical data.

Suppose you are interested in comparing the quality of different hospitals based on infections occurred from surgery. What would be the best way to measure such a variable?

Rate of Infections

What method is useful when comparing two distributions using a stemplot?

back-to-back stemplots

A variable is a characteristic of a

case

To examine the relationship between two variables, the variables must be measured from the same _______.

cases

A type of variable where arithmetic operations do not make sense are called _______.

categorical

We have a data set where the cases are college students. One of the variables in the data set is "gender." The values of gender are 1 if the student is male and 2 if the student is female. What type of variable is gender?

categorical

We have a data set where the cases are college students. One of the variables in the data set is "hometown." What type of variable is hometown?

categorical

Suppose you own a pizza delivery company and you are trying to determine the best campus on which to sell pizza. What would be the best measurement to make the comparison?

count of pizzas purchased

The distribution of a categorical variable is displayed using _______.

counts or percentages

Response variables are also called ____________ variables.

dependent

is the use of the regression line for prediction outside the range of values observed for the explanatory variable x.

extrapolation

The tails of a distribution show the _______.

extreme values

in the least square regression equation B0 is the _____

height (intercept)

Large data sets with quantitative variables are best displayed using ________.

histograms

When creating a scatterplot, one should use the _______ axis for the explanatory variable

horizontal

. Explanatory variables are also called ___________ variables.

independent

A variable that explains or causes change to another variable is called a(n) _______ variable.

independent

When drawing a histogram, it is important to

label the vertical axis so the reader can determine the counts or percentage in each class interval.

Categorical variables place cases into ____ group(s).

many

Categorical variables are best displayed by ______.

pie charts or bar graphs

A scatterplot is a graphical tool for displaying the relationship between two __________ variables measured on the same individuals.

quantitative

The units of measurement are an important part of the description of what type of variables?

quantitative

Variables that take numeric values for which arithmetic operations make sense are called _______.

quantitative

We have a data set where the cases are college students. One of the variables in the data set is "age of the student." What type of variable is age of the student?

quantitative

We have a data set where the cases are college students. One of the variables in the data set is "grade." The values of grade are 4 if the student received an A, 3 if the student received a B, 2 if the student received a C, 1 if the student received a D, and 0 if the student received an A. What type of variable is grade?

quantitative

When trying to explain the relationship between two quantitative variables, it would be best to use a _______.

scatterplot

When making histograms, the classes ________.

should be equal width

in the least square regression equation B1 is the _______

slope

Quantitative variables are best displayed using _______.

stemplots

When displaying the distribution of quantitative data, it is best to use

stemplots or histograms

What are labels used for in data sets?

to identify cases

When making a stemplot, it is appropriate to _______ if the values have many digits.

trim the leaves

Variables take on ________.

values

A study is conducted to determine if one can predict the yield of a crop based on the amount of yearly rainfall. The variable _____ is the response variable in this study.

yield of the crop