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: fThe fstudy fnarrative findicated fthat fthe fprevalence fof fdepression fincreased fwith fthe
fgreater fNYHA fclass. fIn fNYHA fclass fIII, f64% fof fthe fsubjects fwere fdepressed, fwhereas f11%
fof fthe fsubjects fwere fdepressed fin fNYHA fclass fI. fThus, fas fthe fNYHA fclass fincreased, fthe
fnumber fof fsub- fjects fwith fdepression fincreased. fThis fis fan fexpected ffinding fbecause fas fthe
fNYHA fclass fincreases, fcardiac fpatients fhave fmore fsevere fphysical fsymptoms, fwhich fusually
fresult fin femotional fdistress, fsuch f as f depression. f Nurses f need f to f actively f assess f cardiac
f patients f for f depression, f especially f those fin fhigher fNYHA fclasses, fso fthey fmight fbe
fdiagnosed fand ftreated fas fneeded.
8. What ffrequency fand fpercent fof fcardiac fpatients fin fthis fstudy fwere fnot fbeing ftreated
fwith fan fantidepressant? fShow fyour fcalculations fand fround fyour fanswer fto fthe
fnearest fwhole fpercent f(%).
Answer: fA ftotal f fof f f106 f fcardiac f fpatients f fparticipated f fin f fthis f fstudy. f fThe f fsample f
fincluded f15 fpatients fwho fwere freceiving fan fantidepressant f(see fTable f1). fThe f fnumber f
fof f fcardiac fpatients f not f treated f for f depression f was f 91 f (106 f – f 15 f = f91). f The f group
f percent f is f calculated fby f the f following f formula: f (group f frequency f ÷ f total f sample
f size) f × f 100%. f For f this f study, f(91 fpatients f÷ f106 fsample fsize) f× f100% f= f0.858 f×
f100% f= f85.8% f= f86%. fThe f ffinal fanswer f is f rounded f to f the f nearest f whole f percent
f as f directed f in f the f question. f You f could f have falso fsubtracted fthe f14% fof fpatients
ftreated fwith fantidepressants ffrom f100% fand fobtained fthe f86% f who f were f not f treated f with
f an f antidepressant.
9. What fwas fthe fpurpose fof fthe f6-minute fwalk ftest f(6MWT)? fWould fthe f6MWT fbe
fuseful fin fclinical fpractice?
Answer: fHa fet fal. f(2018) fstated, f“The f6-min fwalk ftest f(6MWT) fis fa fmeasure fof fthe
fsubmaximal, fsteady-state ffunctional fcapacity” fof fcardiac fpatients. fThis ftest fwould fbe fa
fquick, feasy fway fto fdetermine fa fcardiac fpatient’s ffunctional fstatus fin fa fclinical f fsetting. f
fThis f ffunctional f fstatus fscore f could f be f used f to f determine f the f treatment f plan f to
f promote f or f maintain f functional f statusfof fcardiac fpatients.
, Answer f Guidelines f for f Questions f to f Be f Graded AG f1-3
10. How fwas fexercise fconfidence fmeasured fin fthis fstudy? fWhat fwas fthe flevel fof
fmeasurement ffor fthe fexercise fconfidence fvariable fin fthis fstudy? fProvide fa frationale
ffor fyour fanswer. fAnswer: fExercise fconfidence fof fthe fpatients fwith fheart ffailure f(HF) fin
fthis fstudy fwas fmeasuredfwith fthe fExercise fConfidence fScale fthat fincluded ffour fsubscales
ffocused fon fwalking, fclimbing,flifting f objects f of f graded f weight, f and f running f (see f the
f study f narrative). f This f was f a f rating f scalefwith fvalues franging ffrom f0 fto f100. fThe
fpatients’ fscores ffor fthe fTotal fExercise fConfidence fscalefand f the f subscales f were
f considered f interval-level f data f and f analyzed f with f parametric f statistics,fsuch fas fmeans fand
fSDs f(see fthe fstudy fnarrative; fWaltz fet fal., f2017).
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: fThe fstudy fnarrative findicated fthat fthe fprevalence fof fdepression fincreased fwith fthe
fgreater fNYHA fclass. fIn fNYHA fclass fIII, f64% fof fthe fsubjects fwere fdepressed, fwhereas f11%
fof fthe fsubjects fwere fdepressed fin fNYHA fclass fI. fThus, fas fthe fNYHA fclass fincreased, fthe
fnumber fof fsub- fjects fwith fdepression fincreased. fThis fis fan fexpected ffinding fbecause fas fthe
fNYHA fclass fincreases, fcardiac fpatients fhave fmore fsevere fphysical fsymptoms, fwhich fusually
fresult fin femotional fdistress, fsuch f as f depression. f Nurses f need f to f actively f assess f cardiac
f patients f for f depression, f especially f those fin fhigher fNYHA fclasses, fso fthey fmight fbe
fdiagnosed fand ftreated fas fneeded.
8. What ffrequency fand fpercent fof fcardiac fpatients fin fthis fstudy fwere fnot fbeing ftreated
fwith fan fantidepressant? fShow fyour fcalculations fand fround fyour fanswer fto fthe
fnearest fwhole fpercent f(%).
Answer: fA ftotal f fof f f106 f fcardiac f fpatients f fparticipated f fin f fthis f fstudy. f fThe f fsample f
fincluded f15 fpatients fwho fwere freceiving fan fantidepressant f(see fTable f1). fThe f fnumber f
fof f fcardiac fpatients f not f treated f for f depression f was f 91 f (106 f – f 15 f = f91). f The f group
f percent f is f calculated fby f the f following f formula: f (group f frequency f ÷ f total f sample
f size) f × f 100%. f For f this f study, f(91 fpatients f÷ f106 fsample fsize) f× f100% f= f0.858 f×
f100% f= f85.8% f= f86%. fThe f ffinal fanswer f is f rounded f to f the f nearest f whole f percent
f as f directed f in f the f question. f You f could f have falso fsubtracted fthe f14% fof fpatients
ftreated fwith fantidepressants ffrom f100% fand fobtained fthe f86% f who f were f not f treated f with
f an f antidepressant.
9. What fwas fthe fpurpose fof fthe f6-minute fwalk ftest f(6MWT)? fWould fthe f6MWT fbe
fuseful fin fclinical fpractice?
Answer: fHa fet fal. f(2018) fstated, f“The f6-min fwalk ftest f(6MWT) fis fa fmeasure fof fthe
fsubmaximal, fsteady-state ffunctional fcapacity” fof fcardiac fpatients. fThis ftest fwould fbe fa
fquick, feasy fway fto fdetermine fa fcardiac fpatient’s ffunctional fstatus fin fa fclinical f fsetting. f
fThis f ffunctional f fstatus fscore f could f be f used f to f determine f the f treatment f plan f to
f promote f or f maintain f functional f statusfof fcardiac fpatients.
, Answer f Guidelines f for f Questions f to f Be f Graded AG f1-3
10. How fwas fexercise fconfidence fmeasured fin fthis fstudy? fWhat fwas fthe flevel fof
fmeasurement ffor fthe fexercise fconfidence fvariable fin fthis fstudy? fProvide fa frationale
ffor fyour fanswer. fAnswer: fExercise fconfidence fof fthe fpatients fwith fheart ffailure f(HF) fin
fthis fstudy fwas fmeasuredfwith fthe fExercise fConfidence fScale fthat fincluded ffour fsubscales
ffocused fon fwalking, fclimbing,flifting f objects f of f graded f weight, f and f running f (see f the
f study f narrative). f This f was f a f rating f scalefwith fvalues franging ffrom f0 fto f100. fThe
fpatients’ fscores ffor fthe fTotal fExercise fConfidence fscalefand f the f subscales f were
f considered f interval-level f data f and f analyzed f with f parametric f statistics,fsuch fas fmeans fand
fSDs f(see fthe fstudy fnarrative; fWaltz fet fal., f2017).
