Chapter 1 - Statistics

SHORT ANSWER

	1.	Identify the following statement as descriptive in nature, or as inferential: “The average
age of 500 surveyed students in your institution is 23 years.”

ANS:	
Descriptive

PTS:	1

	2.	Identify the following statement as descriptive in nature, or as inferential: “Based on a
sample of 10,000 Americans, it is fair to say that 70% of all American are overweight.”

ANS:	
Inferential

PTS:	1

	3.	Identify the following statement as descriptive in nature, or as inferential: “Based on a
sample of 20,000 college students, we may conclude that 80% of all college students
dislike true-false questions.”

ANS:	
Inferential

PTS:	1

	4.	Identify the following statement as descriptive in nature, or as inferential: “80% of
students in your statistics class dislike true-false questions.”

ANS:	
Descriptive

PTS:	1

	5.	A population is the complete collection of individuals or objects or events whose
properties are to be analyzed.

ANS:	
T

PTS:	1

	6.	A variable is a characteristic of interest about each individual element of a population or
sample.

ANS:	
T

PTS:	1

	7.	The “number of rotten oranges per shipping crate” is an example of a quantitative
variable.

ANS:	
T

PTS:	1

	8.	Identify the statement “A poll of registered voters asking which candidate they support” as
an example of (1) nominal, (2) ordinal, (3) discrete, or (4) continuous variables.

ANS:	
Nominal

PTS:	1

	9.	Identify the statement “The length of time required for a wound to heal when using a new
medicine.” as an example of (1) nominal, (2) ordinal, (3) discrete, or (4) continuous
variables.

ANS:	
Continuous

PTS:	1

	10.	Identify the statement “The distance first-year college women can kick a football.” as an
example of (1) nominal, (2) ordinal, (3) discrete, or (4) continuous variables.

ANS:	
Continuous

PTS:	1

	11.	Identify the statement “The number of pages per job coming off a computer printer.” as
an example of (1) nominal, (2) ordinal, (3) discrete, or (4) continuous variables.

ANS:	
Discrete

PTS:	1

	12.	Identify the statement “The kind of tree used as a Christmas tree.” as an example of (1)
nominal, (2) ordinal, (3) discrete, or (4) continuous variables.

ANS:	
Nominal

PTS:	1

	13.	Describe in detail how you would select a 4% systematic sample of the adults in a nearby
large city in order to complete a survey about a political issue.

ANS:	
Randomly select an integer between 1 and 25 (100/x = 100/4 = 25). This integer
represents the first item in the sample. Then, select every 25th data item thereafter until
you have the desired number of data for the sample.

PTS:	1

	14.	Explain why the polls that are so frequently quoted during early returns on Election Day
TV coverage are an example of cluster sampling.

ANS:	
Each precinct is considered a cluster, and not all precincts are sampled.

PTS:	1

	15.	If we desire to select a 4% systematic sample, first we will randomly select one element
from the first 40 elements, and then proceed to select every 4th item thereafter until we
have the desired number of data for our sample.

ANS:	
F

PTS:	1

	16.	In general, probability samples are samples in which the elements to be selected are
drawn on the basis of probability in such a way that each element in the population has
the same probability of being selected as part of the sample.

ANS:	
F

PTS:	1

	17.	When a judgment sample is drawn, the person selecting the sample chooses items in
such a way that every element in the population has an equal probability of being chosen.

ANS:	
F

PTS:	1

NUMERIC RESPONSE

Select twenty employees currently working at a local supermarket and collect data for the
following four variables:
W: Marital status
X: number of children they have
Y: total cost of cloth and toys they spend every year for their children
Z: method of payment used for purchasing cloth and toys

	1.	Classify the three variables as nominal, ordinal, discrete, or continuous.

ANS:	W – nominal, X - discrete, Y - continuous (cost rounded to nearest cent), Z – nominal

PTS:	1

At Central Michigan University, 500 students are randomly selected and asked the distance of
their commute to campus. From this group a mean of 15.6 miles is computed.

	2.	What is the variable of interest?

ANS:	The commute distance for students to campus

PTS:	1

An office supply warehouse has boxes of pencils, 100 pencils to the box. Information about the
entire warehouse as well as a sample of the boxes is shown below:

Number of defectives
per box	Number of boxes
(in warehouse)	Number of boxes
(in sample)	
0	1500	50	
1	250	20	
2	75	3	
3	40	3	
4	10	1	

	3.	Describe the population.

ANS:	All boxes of pencils in the warehouse

PTS:	1

	4.	Describe the sample.

ANS:	The boxes of pencils sampled.

PTS:	1

A quality-control inspector selects assembled parts from an assembly line and records the
information concerning each part as: A: defective or nondefective, B: the employee number of the individual who assembled the part, and C: the weight of the part.

	5.	What is the population?

ANS:	All assembled parts from the assembly line

PTS:	1

	6.	Is the population finite or infinite? Why?

ANS:	
Infinite; since all assembled parts from the assembly line can’t be (or couldn’t be)
physically listed.

PTS:	1

	7.	What is the sample?

ANS:	The parts checked

PTS:	1

	8.	Classify the three variables as either attribute or quantitative.

ANS:	A: attribute, B: attribute (it identifies the assembler), C: quantitative

PTS:	1

Select ten students currently enrolled at your college and collect data for these three variables:
X: number of courses enrolled in, Y: total cost of textbooks and supplies for courses, and Z:
method of payment used for textbooks and supplies

	9.	What is the population?

ANS:	All students currently enrolled at the college

PTS:	1

	10.	Is the population finite or infinite?

ANS:	Finite

PTS:	1

	11.	What is the sample?

ANS:	The 10 students selected

PTS:	1

	12.	Classify the three variables as nominal, ordinal, discrete, or continuous.

ANS:	X: discrete, Y: continuous (cost rounded to nearest cent), Z: nominal

PTS:	1