Solution Manual for
Statistics for Nursing
Research A Workbook
for Evidence-Based
Practice 3rd Edition
Susan Grove Daisha
,Answer Guidelines for Questions to Be Graded
EXERCISE
Identifying Levels of
Measurement: Nominal,
Ordinal, Interval, and Ratio
1
The questions are in bold followed by answers.
1. In Table 1, identify the level of measurement for the current therapy variable. Provide a
rationale for your answer.
Answer: The current therapy variable was measured at the nominal level. These drug categories
were probably developed to be exhaustive for this study and included the categories of drugs the
subjects were receiving. However, the categories are not exclusive, since patients are usually on
more than one category of these drugs to manage their health problems. The current therapies
are not measured at the ordinal level because they cannot be rank ordered, since no drug category
can be considered more or less beneficial than another drug category (see Figure 1-1; Grove &
Gray, 2019).
2. What is the mode for the current therapy variable in this study? Provide a rationale for
your answer.
Answer: The mode for current therapy was β blocker. A total of 100 (94%) of the cardiac patients
were receiving this category of drug, which was the most common prescribed drug for this
sample.
3. What statistics were conducted to describe the BMI of the cardiac patients in this sample?
Discuss whether these analysis techniques were appropriate or inappropriate.
Answer: BMI was described with a mean and standard deviation (SD). BMI measurement resulted
in ratio-level data with continuous values and an absolute zero (Stone & Frazier, 2017). Ratio-
level data should be analyzed with parametric statistics such as the mean and SD (Grove & Gray,
2017; Knapp, 2017).
4. Researchers used the following item to measure registered nurses’ (RNs) income in a study:
What category identifies your current income as an RN?
a. Less than $50,000
b. $50,000 to 59,999
c. $60,000 to 69,999
d. $70,000 to 80,000
e. $80,000 or greater
What level of measurement is this income variable? Does the income variable follow the
rules outlined in Figure 1-1? Provide a rationale for your answer.
Answer: In this example, the income variable is measured at the ordinal level. The income catego-
ries are exhaustive, ranging from less than $50,000 to greater than $80,000. The two open-ended
AG 1-1
,AG 1-2 Answer Guidelines for Questions to Be Graded
categories ensure that all salary levels are covered. The categories are not exclusive, since catego-
ries (d) and (e) include an $80,000 salary, so study participants making $80,000 might mark
either (d) or (e) or both categories, resulting in erroneous data. Category (e) could be changed
to greater than $80,000, making the categories exclusive. The categories can be rank ordered
from the lowest salary to the highest salary, which is consistent with ordinal data (Grove &
Gray, 2019; Waltz et al., 2017).
5. What level of measurement is the CDS score? Provide a rationale for your answer.
Answer: The CDS score is at the interval level of measurement. The CDS is a 26-item Likert
scale developed to measure depression in cardiac patients. Study participants rated their symp-
toms on a scale of 1 to 7, with higher numbers indicating increased severity in the depression
symptoms. The total scores for each subject obtained from this multi-item scale are considered
to be at the interval level of measurement (Gray et al., 2017; Waltz et al., 2017).
6. Were nonparametric or parametric analysis techniques used to analyze the CDS scores for
the cardiac patients in this study? Provide a rationale for your answer.
Answer: Parametric statistics, such as mean and SD, were conducted to describe CDS scores
for study participants (see Table 1). CDS scores are interval-level data as indicated in Questions 5,
so parametric statistics are appropriate for this level of data (Gray et al., 2017; Kim & Mallory,
2017).
7. Is the prevalence of depression linked to the NYHA class? Discuss the clinical importance
of this result.
Answer: sThe sstudy snarrative sindicated sthat sthe sprevalence sof sdepression sincreased swith
sthe sgreater sNYHA sclass. sIn sNYHA sclass sIII, s64% sof sthe ssubjects swere sdepressed, swhereas
s11% sof sthe ssubjects swere sdepressed sin sNYHA sclass sI. sThus, sas sthe sNYHA sclass sincreased,
sthe snumber sof ssub- sjects swith sdepression sincreased. sThis sis san sexpected sfinding sbecause sas
sthe sNYHA sclass sincreases, scardiac spatients shave smore ssevere sphysical ssymptoms, swhich
susually sresult sin semotional sdistress, ssuch s as s depression. s Nurses s need s to s actively s assess
s cardiac s patients s for s depression, s especially s those sin shigher sNYHA sclasses, sso sthey smight sbe
sdiagnosed sand streated sas sneeded.
8. What sfrequency sand spercent sof scardiac spatients sin sthis sstudy swere snot sbeing
streated swith san santidepressant? sShow syour scalculations sand sround syour sanswer sto
sthe snearest swhole spercent s(%).
Answer: sA stotal s sof s s106 s scardiac s spatients s sparticipated s sin s sthis s sstudy. s sThe s ssample
s sincluded s15 spatients swho swere sreceiving san santidepressant s(see sTable s1). sThe s snumber
s sof s scardiac spatients s not s treated s for s depression s was s 91 s (106 s – s 15 s = s 91). s The
s group s percent s is s calculated sby s the s following s formula: s (group s frequency s ÷ s total
s sample s size) s × s 100%. s For s this s study, s(91 spatients s÷ s106 ssample ssize) s× s100% s=
s0.858 s× s100% s= s85.8% s= s86%. sThe s sfinal sanswer s is s rounded s to s the s nearest
s whole s percent s as s directed s in s the s question. s You s could s have salso ssubtracted sthe s14%
sof spatients streated swith santidepressants sfrom s100% sand sobtained sthe s86% s who s were s not
s treated s with s an s antidepressant.
9. What swas sthe spurpose sof sthe s6-minute swalk stest s(6MWT)? sWould sthe s6MWT sbe
suseful sin sclinical spractice?
Answer: sHa set sal. s(2018) sstated, s“The s6-min swalk stest s(6MWT) sis sa smeasure sof sthe
ssubmaximal, ssteady-state sfunctional scapacity” sof scardiac spatients. sThis stest swould sbe sa
squick, seasy sway sto sdetermine sa scardiac spatient’s sfunctional sstatus sin sa sclinical s ssetting. s
sThis s sfunctional s sstatus sscore s could s be s used s to s determine s the s treatment s plan s to
s promote s or s maintain s functional s statussof scardiac spatients.
, Answer s Guidelines s for s Questions s to s Be s Graded AG s1-3
10. How swas sexercise sconfidence smeasured sin sthis sstudy? sWhat swas sthe slevel sof
smeasurement sfor sthe sexercise sconfidence svariable sin sthis sstudy? sProvide sa srationale
sfor syour sanswer. sAnswer: sExercise sconfidence sof sthe spatients swith sheart sfailure s(HF)
sin sthis sstudy swas smeasuredswith sthe sExercise sConfidence sScale sthat sincluded sfour
ssubscales sfocused son swalking, sclimbing,slifting s objects s of s graded s weight, s and s running
s (see s the s study s narrative). s This s was s a s rating s scaleswith svalues sranging sfrom s0 sto s100.
sThe spatients’ sscores sfor sthe sTotal sExercise sConfidence sscalesand s the s subscales s were
s considered s interval-level s data s and s analyzed s with s parametric s statistics,ssuch sas smeans
sand sSDs s(see sthe sstudy snarrative; sWaltz set sal., s2017).
Statistics for Nursing
Research A Workbook
for Evidence-Based
Practice 3rd Edition
Susan Grove Daisha
,Answer Guidelines for Questions to Be Graded
EXERCISE
Identifying Levels of
Measurement: Nominal,
Ordinal, Interval, and Ratio
1
The questions are in bold followed by answers.
1. In Table 1, identify the level of measurement for the current therapy variable. Provide a
rationale for your answer.
Answer: The current therapy variable was measured at the nominal level. These drug categories
were probably developed to be exhaustive for this study and included the categories of drugs the
subjects were receiving. However, the categories are not exclusive, since patients are usually on
more than one category of these drugs to manage their health problems. The current therapies
are not measured at the ordinal level because they cannot be rank ordered, since no drug category
can be considered more or less beneficial than another drug category (see Figure 1-1; Grove &
Gray, 2019).
2. What is the mode for the current therapy variable in this study? Provide a rationale for
your answer.
Answer: The mode for current therapy was β blocker. A total of 100 (94%) of the cardiac patients
were receiving this category of drug, which was the most common prescribed drug for this
sample.
3. What statistics were conducted to describe the BMI of the cardiac patients in this sample?
Discuss whether these analysis techniques were appropriate or inappropriate.
Answer: BMI was described with a mean and standard deviation (SD). BMI measurement resulted
in ratio-level data with continuous values and an absolute zero (Stone & Frazier, 2017). Ratio-
level data should be analyzed with parametric statistics such as the mean and SD (Grove & Gray,
2017; Knapp, 2017).
4. Researchers used the following item to measure registered nurses’ (RNs) income in a study:
What category identifies your current income as an RN?
a. Less than $50,000
b. $50,000 to 59,999
c. $60,000 to 69,999
d. $70,000 to 80,000
e. $80,000 or greater
What level of measurement is this income variable? Does the income variable follow the
rules outlined in Figure 1-1? Provide a rationale for your answer.
Answer: In this example, the income variable is measured at the ordinal level. The income catego-
ries are exhaustive, ranging from less than $50,000 to greater than $80,000. The two open-ended
AG 1-1
,AG 1-2 Answer Guidelines for Questions to Be Graded
categories ensure that all salary levels are covered. The categories are not exclusive, since catego-
ries (d) and (e) include an $80,000 salary, so study participants making $80,000 might mark
either (d) or (e) or both categories, resulting in erroneous data. Category (e) could be changed
to greater than $80,000, making the categories exclusive. The categories can be rank ordered
from the lowest salary to the highest salary, which is consistent with ordinal data (Grove &
Gray, 2019; Waltz et al., 2017).
5. What level of measurement is the CDS score? Provide a rationale for your answer.
Answer: The CDS score is at the interval level of measurement. The CDS is a 26-item Likert
scale developed to measure depression in cardiac patients. Study participants rated their symp-
toms on a scale of 1 to 7, with higher numbers indicating increased severity in the depression
symptoms. The total scores for each subject obtained from this multi-item scale are considered
to be at the interval level of measurement (Gray et al., 2017; Waltz et al., 2017).
6. Were nonparametric or parametric analysis techniques used to analyze the CDS scores for
the cardiac patients in this study? Provide a rationale for your answer.
Answer: Parametric statistics, such as mean and SD, were conducted to describe CDS scores
for study participants (see Table 1). CDS scores are interval-level data as indicated in Questions 5,
so parametric statistics are appropriate for this level of data (Gray et al., 2017; Kim & Mallory,
2017).
7. Is the prevalence of depression linked to the NYHA class? Discuss the clinical importance
of this result.
Answer: sThe sstudy snarrative sindicated sthat sthe sprevalence sof sdepression sincreased swith
sthe sgreater sNYHA sclass. sIn sNYHA sclass sIII, s64% sof sthe ssubjects swere sdepressed, swhereas
s11% sof sthe ssubjects swere sdepressed sin sNYHA sclass sI. sThus, sas sthe sNYHA sclass sincreased,
sthe snumber sof ssub- sjects swith sdepression sincreased. sThis sis san sexpected sfinding sbecause sas
sthe sNYHA sclass sincreases, scardiac spatients shave smore ssevere sphysical ssymptoms, swhich
susually sresult sin semotional sdistress, ssuch s as s depression. s Nurses s need s to s actively s assess
s cardiac s patients s for s depression, s especially s those sin shigher sNYHA sclasses, sso sthey smight sbe
sdiagnosed sand streated sas sneeded.
8. What sfrequency sand spercent sof scardiac spatients sin sthis sstudy swere snot sbeing
streated swith san santidepressant? sShow syour scalculations sand sround syour sanswer sto
sthe snearest swhole spercent s(%).
Answer: sA stotal s sof s s106 s scardiac s spatients s sparticipated s sin s sthis s sstudy. s sThe s ssample
s sincluded s15 spatients swho swere sreceiving san santidepressant s(see sTable s1). sThe s snumber
s sof s scardiac spatients s not s treated s for s depression s was s 91 s (106 s – s 15 s = s 91). s The
s group s percent s is s calculated sby s the s following s formula: s (group s frequency s ÷ s total
s sample s size) s × s 100%. s For s this s study, s(91 spatients s÷ s106 ssample ssize) s× s100% s=
s0.858 s× s100% s= s85.8% s= s86%. sThe s sfinal sanswer s is s rounded s to s the s nearest
s whole s percent s as s directed s in s the s question. s You s could s have salso ssubtracted sthe s14%
sof spatients streated swith santidepressants sfrom s100% sand sobtained sthe s86% s who s were s not
s treated s with s an s antidepressant.
9. What swas sthe spurpose sof sthe s6-minute swalk stest s(6MWT)? sWould sthe s6MWT sbe
suseful sin sclinical spractice?
Answer: sHa set sal. s(2018) sstated, s“The s6-min swalk stest s(6MWT) sis sa smeasure sof sthe
ssubmaximal, ssteady-state sfunctional scapacity” sof scardiac spatients. sThis stest swould sbe sa
squick, seasy sway sto sdetermine sa scardiac spatient’s sfunctional sstatus sin sa sclinical s ssetting. s
sThis s sfunctional s sstatus sscore s could s be s used s to s determine s the s treatment s plan s to
s promote s or s maintain s functional s statussof scardiac spatients.
, Answer s Guidelines s for s Questions s to s Be s Graded AG s1-3
10. How swas sexercise sconfidence smeasured sin sthis sstudy? sWhat swas sthe slevel sof
smeasurement sfor sthe sexercise sconfidence svariable sin sthis sstudy? sProvide sa srationale
sfor syour sanswer. sAnswer: sExercise sconfidence sof sthe spatients swith sheart sfailure s(HF)
sin sthis sstudy swas smeasuredswith sthe sExercise sConfidence sScale sthat sincluded sfour
ssubscales sfocused son swalking, sclimbing,slifting s objects s of s graded s weight, s and s running
s (see s the s study s narrative). s This s was s a s rating s scaleswith svalues sranging sfrom s0 sto s100.
sThe spatients’ sscores sfor sthe sTotal sExercise sConfidence sscalesand s the s subscales s were
s considered s interval-level s data s and s analyzed s with s parametric s statistics,ssuch sas smeans
sand sSDs s(see sthe sstudy snarrative; sWaltz set sal., s2017).
