Uni Unit t I: Intr ntro to to Biology Pa Part V: Data Pre - - PowerPoint PPT Presentation

Uni Unit t I: Intr ntro to to Biology

Pa Part V: Data Pre Presen entation

• n

Presentation of Experimental Work

• Ta

Tables

• Gr

Graphs

Overall Purpose of Data Table

• Organize infor
• rmation
• n in on
• ne place
• Id

Identify patterns in the data

• He

Help analyze & interpret results

• Help present data to
• 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 ta tables

• 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

• n t
• n the x

x-ax axis

• De

Dependent t variable is place ced

• n t
• n the y

y-ax axis

General Rules for Making Graphs

• Scales o
• f 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

• priat

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 sc scatter pl 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

• r curv

rve

• De

Definition

• n of
• f Best Fit Line or
• r 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

• r
• r cu

curve

Equation of Best Fit Line

• Ta

Take two points that lie on best fit line

• Ca

Calcu cula late the slop lope m = DY/ Y/DX

• Ex

Extend the line until it intersects the y-ax axis at x=0; 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 1. 1. Cr Creat ate e scat atter er plo lot 2. 2. Dr Draw b bes est f t fit l t line 3. 3. Cal Calculat late e equat ation of li line

Sample Problem

Characteristics of Bar Graphs

• Common t

type o

• f 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