Answers to Open-ended Questions
Chapter 1.
1.52 The drug company is interested in testing the difference between the two drugs.
1.53 a) 6% is a parameter
b) 10% is a statistic
c) If the independent researcher’s sample is random, it may be that the drug causes
side effects in a larger percent of the population than originally estimated.
1.54 a) The population of interest is everyone who lives in the low income
neighborhood.
b) The sample is the 100 people who were interviewed.
c) Their sampling technique is not a good way to represent the low income
neighborhood because it excludes households without telephones.
d) 25% is a statistic
1.55 a) relationship
b) difference
c) difference
1.56 a) descriptive statistics
b) inferential statistics
c) descriptive statistic
1.57 Possible answers include: height, weight, IQ, exam scores, temperature, etc.
1.58 Possible answers include: gender, marital status, eye color, hair color, etc.
1.59 Possible answers include: gold medalists, silver medalists, bronze medalists, non-
medalists, athletes from the United States, figure skaters, etc.
1.60 Possible answers include: selecting every third athlete during the parade at the
opening ceremonies or randomly pulling athletes names out of a hat.
1.61 Random samples increase our confidence that the data are an accurate reflection of
the population from which the sample was drawn.
Chapter 2.
, 2.49 Possible answers include: gender, year in school, hair color, astrological sign, etc.
2.50 Possible answers include: age, weight, height, temperature, speed, etc.
2.51 a) gender
b) class rank
c) temperature
d) length
2.52 Dr. Smith has data that began as continuous data and were then changed into
categorical (nominal, discrete) data.
2.53 a) can designs
b) sales
c) continuous
2.54 a) gender
b) whether or not you major in the sciences
c) discrete
2.55 Random assignment to groups increases our confidence that observed differences
are a function of the independent variable rather than pre-existing differences in the two
groups.
2.56 Possible answers include: assign everyone a number and use the table of random
numbers to select people, pull names out of a hat, or use a computer to generate a random
list.
2.57 a) 95
4
b) X or ∑ X
1
2.58 a) 13
b) 39
c) 26
Chapter 3.
3.48 Sample stem and leaf plot
Stem Leaf
,0 1235679
1 0134456689
2 00124455678899
3 0112225579
4 02235679
5 0019
, 3.49 A chart and a graphical presentation are both acceptable answers.
Score Frequency Score Frequency Score Frequency
1 1 21 1 41 0
2 1 22 1 42 2
3 1 23 0 43 1
4 0 24 2 44 0
5 1 25 2 45 1
6 1 26 1 46 1
7 1 27 1 47 1
8 0 28 2 48 0
9 1 29 2 49 1
10 1 30 1 50 2
11 1 31 2 51 1
12 0 32 3 52 0
13 1 33 0 53 0
14 2 34 0 54 0
15 1 35 3 55 0
16 2 36 0 56 0
17 0 37 1 57 0
18 1 38 0 58 0
19 1 39 1 59 1
20 2 40 1 60 0
Chapter 1.
1.52 The drug company is interested in testing the difference between the two drugs.
1.53 a) 6% is a parameter
b) 10% is a statistic
c) If the independent researcher’s sample is random, it may be that the drug causes
side effects in a larger percent of the population than originally estimated.
1.54 a) The population of interest is everyone who lives in the low income
neighborhood.
b) The sample is the 100 people who were interviewed.
c) Their sampling technique is not a good way to represent the low income
neighborhood because it excludes households without telephones.
d) 25% is a statistic
1.55 a) relationship
b) difference
c) difference
1.56 a) descriptive statistics
b) inferential statistics
c) descriptive statistic
1.57 Possible answers include: height, weight, IQ, exam scores, temperature, etc.
1.58 Possible answers include: gender, marital status, eye color, hair color, etc.
1.59 Possible answers include: gold medalists, silver medalists, bronze medalists, non-
medalists, athletes from the United States, figure skaters, etc.
1.60 Possible answers include: selecting every third athlete during the parade at the
opening ceremonies or randomly pulling athletes names out of a hat.
1.61 Random samples increase our confidence that the data are an accurate reflection of
the population from which the sample was drawn.
Chapter 2.
, 2.49 Possible answers include: gender, year in school, hair color, astrological sign, etc.
2.50 Possible answers include: age, weight, height, temperature, speed, etc.
2.51 a) gender
b) class rank
c) temperature
d) length
2.52 Dr. Smith has data that began as continuous data and were then changed into
categorical (nominal, discrete) data.
2.53 a) can designs
b) sales
c) continuous
2.54 a) gender
b) whether or not you major in the sciences
c) discrete
2.55 Random assignment to groups increases our confidence that observed differences
are a function of the independent variable rather than pre-existing differences in the two
groups.
2.56 Possible answers include: assign everyone a number and use the table of random
numbers to select people, pull names out of a hat, or use a computer to generate a random
list.
2.57 a) 95
4
b) X or ∑ X
1
2.58 a) 13
b) 39
c) 26
Chapter 3.
3.48 Sample stem and leaf plot
Stem Leaf
,0 1235679
1 0134456689
2 00124455678899
3 0112225579
4 02235679
5 0019
, 3.49 A chart and a graphical presentation are both acceptable answers.
Score Frequency Score Frequency Score Frequency
1 1 21 1 41 0
2 1 22 1 42 2
3 1 23 0 43 1
4 0 24 2 44 0
5 1 25 2 45 1
6 1 26 1 46 1
7 1 27 1 47 1
8 0 28 2 48 0
9 1 29 2 49 1
10 1 30 1 50 2
11 1 31 2 51 1
12 0 32 3 52 0
13 1 33 0 53 0
14 2 34 0 54 0
15 1 35 3 55 0
16 2 36 0 56 0
17 0 37 1 57 0
18 1 38 0 58 0
19 1 39 1 59 1
20 2 40 1 60 0
