scientific method h o vs h a types of studies experimental vs observational n.
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Science & Study Basics- Overview

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  1. Ecological Methodology LEC-01aAlthoff Science & Study Basics- Overview Scientific Method: HO vs. HATypes of Studies: Experimental vs. Observational

  2. EXPERIMENTAL INTERPRETATION ANALYSIS: Trends/Baseline EVALUATION OF METHODS INVENTORY & MONITORING

  3. Scientific Method Observation(s) Question Hypothesis Test does _______ hypothesis: make additional predictions and test them Test does _______ support hypothesis: revise hypothesis or pose new one Prediction Test: Experimental or Additional observation

  4. Activity: Put these in proper order • Conclusion • Experiment • Hypothesis • Observation(question) • Theory

  5. Some important terms • _______ = sample unit left as “normal” or untreated • _______ = sample unit that something “different” is done to it • _______ = assumes no bias due to human subjectivity • __________________ = independent variable • __________________ = dependent variable

  6. Observational vs. Experimental Studies • Observational: no controls (usually), trying to determine basics, learn patterns, trends, characteristics • Experimental: control (usually), have basic knowledge of subject that enables one to “separate” into treatment groups

  7. Hypothesis • = null hypothesis….essentially says “no differences” • = alternative hypothesis….essentially says “found differences”…with statistical evidence to support that

  8. Observational vs. Experimental Studies • Observational: generally summarize data using _____________ statistics • Experimental: determine if differences between treatments are “real” using _______________ statistics

  9. Statistics • Descriptive statistics: central tendency: mean, median, mode spread: range, variance, standard deviation, standard error relationship: correlation (Pearson, Spearman) • Inferential statistics: parametric: t-test, F-test, Analysis of Variance (ANOVA), chi-squared non-parametric: sign test, Kruskal-Wallis test, Friedman test • Models: Akaikae Information Criterion (AIC), Structural Equation Modeling (SEM)

  10. Quail Eggs: Does Size Matter? • Not all eggs laid are the same….can vary by: 1) weight/mass 2) yolk composition (protein & lipid %) 3) albumen composition (protein & water %) 4) shell thickness

  11. Quail Eggs: Key components 3 2 Pre-incubation Mid-incubation

  12. Quail Eggs: Does Size Matter? • Normally take 23-24 days to hatch from start of incubation • Young born are __________…meaning they are “ready” to go (aka leave nest) within 6-24 hours after hatching • Eggs must be kept at 99-100 oF (99.5 oFbest) for the duration of the incubation period • 3 ways for us to “check” on development: 1) _______ eggs (expect weight will decrease) 2) _______ eggs (expect air space to increase) 3) _______ eggs (expect “light”/”dark” areas)

  13. Quail Eggs: Checking Egg Status • Weigh – using digital platform scale

  14. Quail Eggs: Checking Egg Status • Float – in beaker of water Sink Semi-float Float

  15. Quail Eggs: Checking Egg Status • Candling

  16. The “Study” Design Starting with 100+ eggs Placing in incubator with egg turner

  17. Basics…. • Overall, eggs pre-incubation weighed from ________________ grams • To have “clear separation” of small vs. large eggs, will consider only eggs weight 11.3 g or less as _________12.4 g or greater as ___________ • Response variable: hatch within 24 hours of first hatch (= H24)  _______ or less ____ or greater 

  18. Hypothesis & Statistical Test • H0 - No difference in H24 between small and large eggs • HA - Difference in H24 between small and large eggs • Evaluate using Chi-Squared (X2) Hatch in H24 Small eggs (<11.3) (N = 28) Large eggs (<12.4) (N = 31)