Download Unit 2 Summary Lab Assignment Name

MODULE 7. QUANTIFITYING VARIABILITY RELATIVE TO THE MEAN
Module 7.6
Unit 2 Summary Lab
Unit2SummaryLabAssignment
Name:_________________________________________________
LearningGoal:Forthedistributionofaquantitativevariable,describetheoverallpattern
(shape,center,andspread)andstrikingdeviationsfromthepattern.
SpecificLearningObjective:
• Usetechnologytogenerategraphsandnumericalsummariestocompare
distributionsofaquantitativevariable.
• Compareandcontrastdifferentwaysofidentifyingintervalsof“typical”datavalues.
1) Supposethatyouaredesigningaone-size-fits-mostunisexbeltforadults.Aone-sizefits-mostbeltcannotfiteveryone,butwewantittofit“typical”adults.Wewilluse
technologytoidentify“typical”intervalsofwaistmeasurementsforthe507adultsin
thedatasetBodyMeasurement.txtusingideasfromUnit2.
(NeedhelpwithStatCrunch?SeetheinstructionsintheTechnologyAppendix.)
a) Forthewaistgirth,findanintervaloftypicalmeasurementsusingquartiles.
The typical interval is from Q1 to Q3: "from 68 cm to 84.5 cm"
b) Findanintervaloftypicalmeasurementsusingmeanandstandarddeviation.
The typical interval is from
mean - std dev to
mean + std dev
76.98 - 11.01 to
76.98 + 11.01
65.97 cm
to
87.99 cm
c) Whichintervaldoyouthinkisthebesttouseinthissituationtoidentifytypical
measurements?Why?
Q1 to Q3: the interval "from 68 cm to 84.5 cm" is best to identify the
typical measurements, because the distribution is right-skewed.
95
96
UNIT 2. SUMMARIZING DATA GRAPHICALLY AND NUMERICALLY
2) OpentheBodyTempandHeartRatedataset.
a) Whatheartratedoyouthinkbestrepresentsthemeninthissample?Whatabout
thewomen?Didyouchooseameanoramedianorsomeothernumber?Why?
The mean = 73 and the median = 73.4 beats/minutes both represent men in
this sample well, because their distribution is symmetric. The median = 76
best represents women in this sample, because their distribution is skewed to
the right.
b) Whichgenderhasmorevariabilityintheirheartrates?Supportyouranswer.
Women have more variability in heart rates.
The IQR for women is 12. The IQR for men is 8.
(The standard deviation for women is 8.1. The standard deviation for men is
5.9. However, the IQR is a better statistic than the std dev, because the
women's distribution is skewed.)
c) Giveanintervalof“normal”heartratesforeachgenderusingeitherquartilesor
meanandSD.Brieflyexplainwhyyouchosethemeasuresyouused.
"Normal " heart rates for women (Q1 to Q3): interval is "from 68 to 80"
"Normal " heart rates for men (Q1 to Q3): interval is "from 70 to 78"
We use quartiles because the distribution for women is skewed.
d) Basedonthisdata,whatdoyouthinknursesshoulduseasanintervaloftypical
heartratesforadults?Shouldtheyusedifferentintervalsformenandwomen?Why
orwhynot?
I think nurses should use different intervals of typical heart rates for adult men
vs. adult women. They should use the intervals in Part c) above, because men's
normal heart rates and women's normal heart rates have different spreads.