W A L D E N U N I V E R S I T Y P U B H 6 0 3 2 / 8 0 3 2 S P S S R E V E A L E D P U B H 6 0 3 3 / 8 0 3 3 I N T E R P R E T A T I O N & A P P O F D A T A T yp es of V ariables & L evels of M easu rem en t T yp es of V ariables y A variable is an y factor, trait, con d ition , or d isease th at exists in d ifferin g am ou n ts or typ es. y E xp erim en tal an d observation al stu d ies con sist of several typ es of variables. y A ll stu d ies in volve at least on e in d ep en d en t variable (IV ) an d on e d ep en d en t variable (D V ). { G et acqu ain ted w ith id en tifyin g th e IV an d D V . It’s th e first step in d evelop in g a research qu estion . D ep en d en t V ariable (D V ) y D isease or h ealth ou tcom e of in terest y P resu m ed effect of a stu d y y Syn on ym s: O u tcom e or C riterion variable y E xam p les: { C an cer { D iabetes { H IV statu s { C H D m ortality { D en gu e in fection In d ep en d en t V ariable (IV ) y P red ictor or exp osu re of in terest y P resu m ed cau se of a stu d y y Syn on ym s: E xp erim en tal, P red ictor, or M an ip u lated variable y E xam p les: { A ge { R ace { In com e { B M I { D ru g U se { C on d om U se C on fou n d in g V ariable y A variable th at obscu res th e effects betw een th e IV an d D V y A variable th at th e research er failed to con trol or elim in ate y Syn on ym s: C ovariate, T h ird variable, M ed iatin g variable y E xam p les: { C igarette sm okin g con fou n d s th e effect betw een d rin kin g coffee (IV ) an d h eart d isease (D V ) { D iet, age, an d gen d er con fou n d th e effect betw een lack of exercise (IV ) an d w eigh t gain (D V ) L evels of M easu rem en t y E ach variable can be classified by its level of m easu rem en t. y W e w ill classify accord in g to term s u sed in th e G erstm an (20 16 ) textbook. H ere th ey are listed in ord er of in creasin g p recision : { C ategorical { O rd in al { Q u an titative { It is im p ortan t to u n d erstan d th e d ifferen t levels of m easu rem en t as th ey h elp d eterm in e th e statistical test th at sh ou ld be carried ou t. C ategorical y C lassify observation s in to n am ed categories, w ith n o in trin sic ord erin g of th e categories y C ategories are often assign ed n u m erical valu es as labels (eg., 0 = N o, 1= Y es) y Syn on ym s: N om in al y C ategorical variables w ith 2 levels are also called B in ary or D ich otom ou s y E xam p les: { G en d er: M ale/F em ale { R ace: B lack/W h ite/O th er { M ortality statu s: D ead /A live ...