Uni Unit t I: Intr ntro to to Biology
Pa Part V: Data Pre Presen entation on
Presentation of Experimental Work • Ta Tables • Gr Graphs
Overall Purpose of Data Table • Organize infor ormation on in on one place • Id Identify patterns in the data • He Help analyze & interpret results • Help present data to o reader
Data Tables • Ke Key Characteristics: • Ti Title- • Must b be s specific a and d descri ribe d data t table • Col Column mns/r /rows la labeled wi with h units incl cluded • Ea Easy to view • Al All d data d displayed
Example of Data Table • Ta Table: The number of brine shrimp found in sections of tubing after the shrimp we were exposed to changes in light, pH, or temperature
THINK • Lis List th t the s str trength ths an s and d th the w weakness o ss of th f this is dat data t a table
Overall Purpose of Graphs • Visually d display d data • More e eye-catching t than d data tables ta • Easier t r to s see p pattern rns a across data p points
Relationship Between Data Tables & Graphs • Gr Graphs canno nnot stand alo lone • Mus Must b be p e preceded b by a a d data t table • Da Data tables provide the exp xperimental details • Gr Graph phs pr s provide th the tr trends nds
General Rules for Making Graphs • Must u use g graph p paper, i if drawing b by h hand • Must h have a a g good t title – Y a axis vs. X X a axis • De Depen enden ent v t vs. I Indepen enden ent • Is Is the title le on the right a good ti titl tle? e?
General Rules for Making Graphs • In Inde depende dent variab able le is plac aced ed on the x on t x-ax axis • De Dependent t variable is place ced on t on the y y-ax axis
General Rules for Making Graphs • Scales o of X X a and Y Y a axis: • Range e of x and y axis must be e appropriate e for the e data pres esen ented • Each scale e MUST be e equal inter ervals • Scales es are e not neces essarily the e same e on each axis • Commonly each axis starts at zer ero
General Rules for Making Graphs • Ea Each axis must have a a label with h ap approp opriat ate units
General Rules for Making Graphs • Mu Multiple lines or bars mu must include a ke key • Ke Keys indicate w what each b bar o r or l r line re repre resents
Line Graphs • Co Compar ares es relat lationship p between een x x an and y va variable • Sho Shows t the ri e rise & f e & fall o all of v val alues es • Re Represents continuous data • Choose e any point on the e x axis and predict, from the e graph, the e value e of y • Us Usuall ally m mad ade w e when en all d all dat ata i a is qu quantitative
Construction of a Line Graph • Pl Plot the data as separate poi points wit s with sy symbols a bols as a s a scatter pl sc plot • Look f for r r relationships between t the t two v vari riables
Best Fit Line • Do Do not t co connect t th the points in th the sca catter plot • Ra Rather, d , draw a w a b best f fit it li line or c or curv rve • De Definition on of of Best Fit Line or or Curve: • St Strai aight li line o e or s r smooth c h curv rve t e that at b bes est r repr pres esen ents t the po e points • Draw a line e or curve e that comes es as close e to as many points as possible • The e line e drawn should have e equal number er of points above e and below the e line e or or cu curve
Equation of Best Fit Line • Ta Take two points that lie on best fit line lope m = D Y/ Y/ D X • Ca Calcu cula late the slop axis at x = 0; • Ex Extend the line until it intersects the y-ax 0; eq equals the y-in intercep ept (b) • Plu Plug the y-in intercep ept and slope in into the equation of line ine y = mx mx+b +b
Sample Problem • Ta Table 1: % seed germination versus nickel co conce centration in seeds ds % seed 19 22 40 50 59 80 germination Nickel 5 25 40 60 70 100 Concentration 1. 1. Cr Creat ate e scat atter er plo lot (ng/g) 2. 2. Draw b Dr bes est f t fit l t line 3. 3. Calculat Cal late e equat ation of li line
Sample Problem
Characteristics of Bar Graphs • Common t type o of g graph u used w when • In Independent variable is discontin inuous data • Wh When en th the d e dat ata i a is q quan anti titati ative an e and qu qualitative • Qualitative e Data – water er, milk, et etc… • Discrete e Units – Ye Year 1, 2 and 3
Ans Answer ? wer ?s in in No Note te Guide de
Gr Graphin aphing g Pr Pract ctice
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