Analysis, Interpretation, and Visual Presentation of Experimental Data

Total Page:16

File Type:pdf, Size:1020Kb

Analysis, Interpretation, and Visual Presentation of Experimental Data Chapter to appear in Stevens' Handbook of Experimental Psychology, Volume IV C h a p t e r 16 ANALYSIS, INTERPRETATION, AND VISUAL PRESENTATION OF EXPERIMENTAL DATA Geoffrey R. Loftus, University of Washington The Linear Model 3 Null Hypothesis Significance Testing 4 Problems with The LM and with NHST 4 Pictorial Representations 9 The Use of Confidence Intervals 11 Planned Comparisons (Contrasts) 23 Percent Total Variance Accounted for ( 2) 29 Model Fitting 31 Equivalence Techniques to Investigate Interactions 34 References 38 Following data collection from some experi- techniques best instill understanding in the inves- ment, there arise two goals which should guide tigator to begin with are generally also optimal for subsequent data analysis and data presentation. conveying the data’s meaning to the data’s even- The first goal is for the data collector him or her- tual consumers. self to understand the data as thoroughly as possi- So what are these data-analysis and data- ble in terms of (1) how they may bear on the spe- presentation techniques? It is not possible in a sin- cific question that the experiment was designed to gle chapter or even in a very long book to describe address, (2) what if any surprises the data may them all, because there are an infinite number of have produced, and (3) what, if anything, such them. Although most practicing scientists are surprises may imply about the original questions, equipped with a conceptual foundation with re- related questions, or anything else. The second spect to the basic tools of data analysis and data goal is to determine how to present the data to the presentation, such a foundation is far from suffi- scientific community in a manner that is as clear, cient: it is akin to an artist’s foundation in the tools complete, and intuitively compelling as possible. of color mixing, setting up an easel, understanding This second goal is intimately entwined with the perspective, and the like. To build on this analogy, first: Whatever data analysis and presentation a scientist analyzing any given experiment is like an artist rendering a work of art: Ideally the tools The writing of this chapter was supported by NIMH comprising the practitioner’s foundation should be grant MH41637 to G. Loftus. I thank the late Merrill used creatively rather than dogmatically to pro- Carlsmith for introducing me to numerous of the techniques described in this chapter and David duce a final result that is beautiful, elegant, and Krantz for a great deal of more recent conceptual interesting, instead of ugly, convoluted, and pro- enlightenment about some of the more subtle aspects saic. of hypothesis-testing, confidence intervals and My goal in this chapter is to try to demonstrate planned comparisons. how a number of data-analysis techniques may be STEVENS HANDBOOK OF EXPERIMENTAL PSYCHOLOGY Page 2 used creatively in an effort to understand and con- clearly conveyed to the intended recipients. vey to others the meaning and relevance of a data Somewhere in this chapter is an answer to ap- set. It is not my intent to go over territory that is proximately 70% of these complaints. It is my traditionally covered in statistics texts. Rather, I hope that, among other things, this chapter will have chosen to focus on a limited, but powerful, provide a reference to which I can guide authors arsenal of techniques and associated issues that are whose future work passes across my desk—as an related to, but are not typically part of a standard alternative, that is, to trying to solve what I believe statistics curriculum. I begin this chapter with an to be the world’s data analysis and presentation overview of data analysis as generically carried problems one manuscript at a time. out in psychology, accompanied by a critique of some standard procedures and assumptions, with FOUNDATIONS: THE LINEAR particular emphasis on a critique of null hypothe- sis significance testing (NHST). Next, I discuss a MODEL AND NULL HYPOTHESIS collection of topics that represent some supple- SIGNIFICANCE TESTING ments and/or alternatives to the kinds of standard Suppose that a memory researcher were inter- analysis procedures about which I will have just ested in how stimulus presentation time affects complained. These discussion include (1) a de- memory for a list of words as measured in a free- scription of various types of pictorial representa- recall paradigm. In a hypothetical experiment to tions of data, (2) an overview of the use of confi- answer this question, the investigator might select dence intervals which, I believe, constitutes an J = 5 presentation times consisting of 0.5, 1.0, 2.0, attractive alternative to NHST, (3) a review of the 4.0, and 8.0 sec/word and carry out an experiment benefits of planned comparisons which entail an using a between-subjects design in which n = 20 analysis of percent between-conditions variance subjects are assigned to each of the 5 word- accounted for, (4) a description of techniques in- duration conditions—hence, N = 100 subjects in volving percent total variance accounted for, (5) a all. Each subject sees 20 words, randomly selected brief set of suggestions about presentation of re- from a very large pool of words. For each subject, sults based on mathematical models (meant to the words are presented sequentially on a com- complement the material in the Myung & Pitt puter screen, each word presented for its appropri- chapter) and finally, (6) a somewhat evangelical ate duration. Immediately following presentation description of what I have termed equivalence of the last word, the subject attempts to write techniques. down as many of the words as possible. The in- vestigator then calculates the proportion correct My main expositional strategy is to illustrate number of words (out of the 20 possible) for each through example. In most instances, I have in- subject. vented experiments and associated data to use in the examples. This strategy has the disadvantage The results of this experiment therefore con- that it is somewhat divorced from the real world of sist of 100 numbers: one for each of the 100 sub- psychological data, but has the dominating ad- jects. How are these 100 numbers to be treated in vantage that the examples can be tailored specifi- order to address the original question of how cally to the illustration of particular points. memory performance is affected by presentation time? There are two steps to this data- The logic and mathematical analysis in this interpretation process. The first is the specification chapter is not meant to be formal or complete. For of a mathematical model1, within the context of proofs of various mathematical assertions that I which each subject’s experimentally observed make, it is necessary to consult a mathematically number results from assumed events occurring oriented statistics text. There are a number of such within the subject. There are an infinite number of texts; my personal favorite is Hays (1973), and ways to formulate such a mathematical model. The where appropriate, I supply references to Hays most widely used formulation, on which I will fo- along with specific page numbers. cus on in this chapter, is referred to as the linear My choice of material and the recommenda- model or LM. tions that I selected to include in this chapter have The second step in data interpretation is to been strongly influenced by 35 years of experience carry out a process by which the mathematical in reviewing and journal editing. In the course of model, once specified, is used to answer the ques- these endeavors I have noticed an enormous num- ber of data-analysis and data-presentation tech- niques that have been sadly inimical to insight and 1 I have sometimes observed that the term "mathemati- clarity—and conversely, I have noticed enormous cal model" casts fear into the hearts of many research- numbers of missed opportunities to analyze and ers. However, if it is numbers from an experiment that present data in such a way that the relevance and are to be accounted for, then the necessity of some importance of the findings are underscored and kind of mathematical model is logically inevitable. DATA ANALYSIS, INTERPRETATION AND PRESENTATION Page 3 Table 1. Types of Models. The response measure is R, and the values of independent variables are la- beled X and Y. The model parameters are indicated by Greek letters, and . All models listed are linear models except for the last which is not linear because it includes the product of three parame- ters, i j. Model Model Name R = a + b X + gY Multiple Regression (Additive) R = a + b X + gY + dXY Multiple Regression (Bilinear) R = a + b X + gY + dY2 Multiple Regression (Quadratic in Y) R = a + bi + gj Two-Way ANOVA (Additive) R = a + b i + gj + dij Two-Way ANOVA with Interaction R = a + b X + gj One-Way ANACOVA (Additive) R = a + b i + gj + dbigj Tukey’s one-degree-of-freedom interaction model tion at hand. Note that there are numerous possi- 3. Across the subjects x words population there bilities for how this can be done. The process that is a “grand mean,” denoted m, of the depend- is the most widely used is that of null hypothesis ent variable measured in the experiment. The significance testing, or NHST. grand mean is a theoretical entity, but roughly Most readers of this chapter are probably fa- it can be construed as the number that would miliar with both the LM and the process of NHST. result if all individuals in the target population Nonetheless, to insure a common conceptual and were run in the experiment for an infinite notational foundation, I will describe both of them number of times in all conditions, using in the briefly in the next two sections.
Recommended publications
  • Survey Experiments
    IU Workshop in Methods – 2019 Survey Experiments Testing Causality in Diverse Samples Trenton D. Mize Department of Sociology & Advanced Methodologies (AMAP) Purdue University Survey Experiments Page 1 Survey Experiments Page 2 Contents INTRODUCTION ............................................................................................................................................................................ 8 Overview .............................................................................................................................................................................. 8 What is a survey experiment? .................................................................................................................................... 9 What is an experiment?.............................................................................................................................................. 10 Independent and dependent variables ................................................................................................................. 11 Experimental Conditions ............................................................................................................................................. 12 WHY CONDUCT A SURVEY EXPERIMENT? ........................................................................................................................... 13 Internal, external, and construct validity ..........................................................................................................
    [Show full text]
  • Lab Experiments Are a Major Source of Knowledge in the Social Sciences
    IZA DP No. 4540 Lab Experiments Are a Major Source of Knowledge in the Social Sciences Armin Falk James J. Heckman October 2009 DISCUSSION PAPER SERIES Forschungsinstitut zur Zukunft der Arbeit Institute for the Study of Labor Lab Experiments Are a Major Source of Knowledge in the Social Sciences Armin Falk University of Bonn, CEPR, CESifo and IZA James J. Heckman University of Chicago, University College Dublin, Yale University, American Bar Foundation and IZA Discussion Paper No. 4540 October 2009 IZA P.O. Box 7240 53072 Bonn Germany Phone: +49-228-3894-0 Fax: +49-228-3894-180 E-mail: [email protected] Any opinions expressed here are those of the author(s) and not those of IZA. Research published in this series may include views on policy, but the institute itself takes no institutional policy positions. The Institute for the Study of Labor (IZA) in Bonn is a local and virtual international research center and a place of communication between science, politics and business. IZA is an independent nonprofit organization supported by Deutsche Post Foundation. The center is associated with the University of Bonn and offers a stimulating research environment through its international network, workshops and conferences, data service, project support, research visits and doctoral program. IZA engages in (i) original and internationally competitive research in all fields of labor economics, (ii) development of policy concepts, and (iii) dissemination of research results and concepts to the interested public. IZA Discussion Papers often represent preliminary work and are circulated to encourage discussion. Citation of such a paper should account for its provisional character.
    [Show full text]
  • Combining Epistemic Tools in Systems Biology Sara Green
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Philsci-Archive Final version to be published in Studies of History and Philosophy of Biological and Biomedical Sciences Published online: http://www.sciencedirect.com/science/article/pii/S1369848613000265 When one model is not enough: Combining epistemic tools in systems biology Sara Green Centre for Science Studies, Department of Physics and Astronomy, Ny Munkegade 120, Bld. 1520, Aarhus University, Denmark [email protected] Abstract In recent years, the philosophical focus of the modeling literature has shifted from descriptions of general properties of models to an interest in different model functions. It has been argued that the diversity of models and their correspondingly different epistemic goals are important for developing intelligible scientific theories (Levins, 2006; Leonelli, 2007). However, more knowledge is needed on how a combination of different epistemic means can generate and stabilize new entities in science. This paper will draw on Rheinberger’s practice-oriented account of knowledge production. The conceptual repertoire of Rheinberger’s historical epistemology offers important insights for an analysis of the modelling practice. I illustrate this with a case study on network modeling in systems biology where engineering approaches are applied to the study of biological systems. I shall argue that the use of multiple means of representations is an essential part of the dynamic of knowledge generation. It is because of – rather than in spite of – the diversity of constraints of different models that the interlocking use of different epistemic means creates a potential for knowledge production.
    [Show full text]
  • Experimental Philosophy and Feminist Epistemology: Conflicts and Complements
    City University of New York (CUNY) CUNY Academic Works All Dissertations, Theses, and Capstone Projects Dissertations, Theses, and Capstone Projects 9-2018 Experimental Philosophy and Feminist Epistemology: Conflicts and Complements Amanda Huminski The Graduate Center, City University of New York How does access to this work benefit ou?y Let us know! More information about this work at: https://academicworks.cuny.edu/gc_etds/2826 Discover additional works at: https://academicworks.cuny.edu This work is made publicly available by the City University of New York (CUNY). Contact: [email protected] EXPERIMENTAL PHILOSOPHY AND FEMINIST EPISTEMOLOGY: CONFLICTS AND COMPLEMENTS by AMANDA HUMINSKI A dissertation submitted to the Graduate Faculty in Philosophy in partial fulfillment of the requirements for the degree of Doctor of Philosophy, The City University of New York 2018 © 2018 AMANDA HUMINSKI All Rights Reserved ii Experimental Philosophy and Feminist Epistemology: Conflicts and Complements By Amanda Huminski This manuscript has been read and accepted for the Graduate Faculty in Philosophy in satisfaction of the dissertation requirement for the degree of Doctor of Philosophy. _______________________________ ________________________________________________ Date Linda Martín Alcoff Chair of Examining Committee _______________________________ ________________________________________________ Date Nickolas Pappas Executive Officer Supervisory Committee: Jesse Prinz Miranda Fricker THE CITY UNIVERSITY OF NEW YORK iii ABSTRACT Experimental Philosophy and Feminist Epistemology: Conflicts and Complements by Amanda Huminski Advisor: Jesse Prinz The recent turn toward experimental philosophy, particularly in ethics and epistemology, might appear to be supported by feminist epistemology, insofar as experimental philosophy signifies a break from the tradition of primarily white, middle-class men attempting to draw universal claims from within the limits of their own experience and research.
    [Show full text]
  • Verification and Validation in Computational Fluid Dynamics1
    SAND2002 - 0529 Unlimited Release Printed March 2002 Verification and Validation in Computational Fluid Dynamics1 William L. Oberkampf Validation and Uncertainty Estimation Department Timothy G. Trucano Optimization and Uncertainty Estimation Department Sandia National Laboratories P. O. Box 5800 Albuquerque, New Mexico 87185 Abstract Verification and validation (V&V) are the primary means to assess accuracy and reliability in computational simulations. This paper presents an extensive review of the literature in V&V in computational fluid dynamics (CFD), discusses methods and procedures for assessing V&V, and develops a number of extensions to existing ideas. The review of the development of V&V terminology and methodology points out the contributions from members of the operations research, statistics, and CFD communities. Fundamental issues in V&V are addressed, such as code verification versus solution verification, model validation versus solution validation, the distinction between error and uncertainty, conceptual sources of error and uncertainty, and the relationship between validation and prediction. The fundamental strategy of verification is the identification and quantification of errors in the computational model and its solution. In verification activities, the accuracy of a computational solution is primarily measured relative to two types of highly accurate solutions: analytical solutions and highly accurate numerical solutions. Methods for determining the accuracy of numerical solutions are presented and the importance of software testing during verification activities is emphasized. The fundamental strategy of 1Accepted for publication in the review journal Progress in Aerospace Sciences. 3 validation is to assess how accurately the computational results compare with the experimental data, with quantified error and uncertainty estimates for both.
    [Show full text]
  • Experimental and Quasi-Experimental Designs for Research
    CHAPTER 5 Experimental and Quasi-Experimental Designs for Research l DONALD T. CAMPBELL Northwestern University JULIAN C. STANLEY Johns Hopkins University In this chapter we shall examine the validity (1960), Ferguson (1959), Johnson (1949), of 16 experimental designs against 12 com­ Johnson and Jackson (1959), Lindquist mon threats to valid inference. By experi­ (1953), McNemar (1962), and Winer ment we refer to that portion of research in (1962). (Also see Stanley, 19S7b.) which variables are manipulated and their effects upon other variables observed. It is well to distinguish the particular role of this PROBLEM AND chapter. It is not a chapter on experimental BACKGROUND design in the Fisher (1925, 1935) tradition, in which an experimenter having complete McCall as a Model mastery can schedule treatments and meas~ In 1923, W. A. McCall published a book urements for optimal statistical efficiency, entitled How to Experiment in Education. with complexity of design emerging only The present chapter aspires to achieve an up­ from that goal of efficiency. Insofar as the to-date representation of the interests and designs discussed in the present chapter be­ considerations of that book, and for this rea­ come complex, it is because of the intransi­ son will begin with an appreciation of it. gency of the environment: because, that is, In his preface McCall said: "There afe ex­ of the experimenter's lack of complete con­ cellent books and courses of instruction deal­ trol. While contact is made with the Fisher ing with the statistical manipulation of ex; tradition at several points, the exposition of perimental data, but there is little help to be that tradition is appropriately left to full­ found on the methods of securing adequate length presentations, such as the books by and proper data to which to apply statis­ Brownlee (1960), Cox (1958), Edwards tical procedure." This sentence remains true enough today to serve as the leitmotif of 1 The preparation of this chapter bas been supported this presentation also.
    [Show full text]
  • What Distinguishes Data from Models?
    Paper accepted for publication by European Journal for the Philosophy of Science in December 2018 What Distinguishes Data from Models? Sabina Leonelli University of Exeter Abstract: I propose a framework that explicates and distinguishes the epistemic roles of data and models within empirical inquiry through consideration of their use in scientific practice. After arguing that Suppes’ characterization of data models falls short in this respect, I discuss a case of data processing within exploratory research in plant phenotyping and use it to highlight the difference between practices aimed to make data usable as evidence and practices aimed to use data to represent a specific phenomenon. I then argue that whether a set of objects functions as data or models does not depend on intrinsic differences in their physical properties, level of abstraction or the degree of human intervention involved in generating them, but rather on their distinctive roles towards identifying and characterizing the targets of investigation. The paper thus proposes a characterization of data models that builds on Suppes’ attention to data practices, without however needing to posit a fixed hierarchy of data and models or a highly exclusionary definition of data models as statistical constructs. Structure 1. Introduction ................................................................................................................. 2 2. Data and Models as Representations ......................................................................... 4 3. What Are Data
    [Show full text]
  • Experimental Tests and Qualification of Analytical Methods to Address Thermohydraulic Phenomena in Advanced Water Cooled Reactors
    XA0055000 IAEA-TECDOC-1149 Experimental tests and qualification of analytical methods to address thermohydraulic phenomena in advanced water cooled reactors Proceedings of a Technical Committee meeting held in Villigen, Switzerland, 14-17 September 1998 31/27 INTERNATIONAL ATOMIC ENERGY AGENCY May 2000 IAEA SAFETY RELATED PUBLICATIONS IAEA SAFETY STANDARDS Under the terms of Article III of its Statute, the IAEA is authorized to establish standards of safety for protection against ionizing radiation and to provide for the application of these standards to peaceful nuclear activities. The regulatory related publications by means of which the IAEA establishes safety standards and measures are issued in the IAEA Safety Standards Series. This series covers nuclear safety, radiation safety, transport safety and waste safety, and also general safety (that is, of relevance in two or more of the four areas), and the categories within it are Safety Fundamentals, Safety Requirements and Safety Guides. © Safety Fundamentals (silver lettering) present basic objectives, concepts and principles of safety and protection in the development and application of atomic energy for peaceful purposes. • Safety Requirements (red lettering) establish the requirements that must be met to ensure safety. These requirements, which are expressed as 'shall' statements, are governed by the objectives and principles presented in the Safety Fundamentals. • Safety Guides (green lettering) recommend actions, conditions or procedures for meeting safety requirements. Recommendations in Safety Guides are expressed as 'should' statements, with the implication that it is necessary to take the measures recommended or equivalent alternative measures to comply with the requirements. The IAEA's safety standards are not legally binding on Member States but may be adopted by them, at their own discretion, for use in national regulations in respect of their own activities.
    [Show full text]
  • Ontology Based Analysis of Experimental Data
    Ontology based analysis of experimental data Andrea Splendiani Institute Pasteur, Unité de Biologie Systémique, rue du dr. Roux 25-28, 75015 Paris, France University of Milano-Bicocca, DISCO, via Bicocca degli Arcimboldi 8, 20126 Milano, Italy [email protected] Abstract relating such a large scale experimental evidence to the exist- ing biological knowledge is essential in order to understand We address the problem of linking observations the phenomenon under study. from reality to a semantic web based knowledge Given the vast amount of data generated by high through- base. Concepts in the biological domain are in- put technologies, this necessitates automated support. creasingly being formalized through ontologies, At the same time there is an increasing availability of struc- with an increasing adoption of semantic web stan- tured biological information, in the semantic web framework dards. Atthe same time biologyis becominga data- in particular. The Gene Ontology[Ashburner et al., 2000] ini- centric science, since the increasing availability of tiative provides ontologies describing functions of gene prod- high throughput technologies yields a humanly in- ucts. It currently encompasses more than 17000 terms linked tractable amount of data describing the behavior by relations of inheritance and containment and it is avail- of biological systems at the molecular level. This able in RDF. MGED-ontology1 provides an ontology to de- creates the need for automated support to interpret scribe attributes relevant to mRNA experiments in OWL, and biological data given the pre-existing knowledge the BioPAX[The BioPAX workgroup] initiative is defining a about the biological systems under study. While common standard to represent biological pathways and inter- this is currently addressed through the analysis of action networks in OWL.
    [Show full text]
  • Experimental Philosophy
    Forthcoming in Annual Review of Psychology Experimental Philosophy Joshua Knobe 1,2 , Wesley Buckwalter 3, Shaun Nichols 4, Philip Robbins 5, Hagop Sarkissian 6, and Tamler Sommers 7 1 Program in Cognitive Science, Yale University; 2 Department of Philosophy, Yale University; 3 Department of Philosophy, City University of New York, Graduate Center; 4 Department of Philosophy, University of Arizona; 5 Department of Philosophy, University of Missouri; 6 Department of Philosophy, City University of New York, Baruch College; 7 Department of Philosophy, University of Houston. Abstract Experimental philosophy is a new interdisciplinary field that uses methods normally associated with psychology to investigate questions normally associated with philosophy. The present review focuses on research in experimental philosophy on four central questions. First, why is it that people’s moral judgments appear to influence their intuitions about seemingly nonmoral questions? Second, do people think that moral questions have objective answers, or do they see morality as fundamentally relative? Third, do people believe in free will, and do they see free will as compatible with determinism? Fourth, how do people determine whether an entity is conscious? Keywords: moral psychology, moral relativism, free will, consciousness, causation. INTRODUCTION Contemporary work in philosophy is shot through with appeals to intuition. When a philosopher wants to understand the nature of knowledge or causation or free will, the usual approach is to begin by constructing a series of imaginary cases designed to elicit prereflective judgments about the nature of these phenomena. These prereflective judgments are then treated as important sources of evidence. This basic approach has been applied with great sophistication across a wide variety of different domains.
    [Show full text]
  • EVALUATION of EXPERIMENTAL DATA 2 (THE CURSE of ERROR ANALYSIS) All Experimental Measurements Are Subject to Some Uncertainty, Or Error
    Chapter 2. Errors & Experimental Data 6 EVALUATION OF EXPERIMENTAL DATA 2 (THE CURSE OF ERROR ANALYSIS) All experimental measurements are subject to some uncertainty, or error. At the most fundamental level the uncertainty principle of physics tells us there are some things that we can never know exactly. But most measurements we are likely to make will be limited by ourselves or by our apparatus, and it is useful to learn to deal with these inherent shortcomings in our experiments. Accuracy is a measure of the difference between our measurement and the true value of the quantity we are measuring. High accuracy is what is ultimately desired. In order to obtain accuracy, we often make multiple measurements of the same quantity and the precision is a measure of the spread of these measurements. The meanings of these two terms, accuracy and precision, are thus quite different. A set of measurements may have high precision, but low accuracy. So a student might make three determinations of the chloride content of an unknown and get 43.44%, 43.51% and 43.47%. These results are fairly precise, but the true value might be 41.70% and the determination would not be very accurate. (This is the most common case. Just because a measurement is reproducible does not mean it's right!) Note here that these terms are used in a qualitative, descriptive sense. ACCURACY AND SYSTEMATIC ERRORS How can we evaluate the accuracy of our result? The true result is normally not known, otherwise we would not be making the measurements in the first place.
    [Show full text]
  • Analyzing Experimental Data
    H OW CAN WE U NDERSTAND OUR WATER R ESOURCES? Analyzing Experimental Data he information in this chapter is a following format. The layout for the data table short summary of some topics that is based on the variables for the experiment. Tare covered in depth in the book The first column lists the different values or Students and Research written by Cothron, levels of the independent variable, and the Giese, and Rezba. See the end of this chapter remaining columns list the corresponding for full information on obtaining this book. observed values of the dependent variable. The book is an invaluable resource for any Values for each repeated trial are listed in middle or high school science teacher. separate columns, and then in the last column the average value. The average value will usual- SETTING UP SIMPLE DATA TABLES ly be a mean value, but there are some situa- AND GRAPHS tions where a median value or even mode value would be more appropriate. The labels for the Students should be encouraged to set up independent and dependent variable columns data tables and graphs on a computer should both include the measuring unit if whenever possible. This can be done by applicable, and the table as a whole should be first entering data into a spreadsheet given a title. The example below is a data table program such as Microsoft Excel. for a simple experiment to measure the effect of Making simple data tables... the length of a pendulum string on the number of pendulum swings per minute. A simple data table can be set up in the THE EFFECT OF LENGTH OF PENDULUM STRING ON THE NUMBER OF SWING CYCLES PER MINUTE Length of Number of Swing Cycles per Minute Pendulum String (cm) Trial 1 Trial 2 Trial 3 Average 30 50 70 90 A NALYZING E XPERIMENTAL D ATA 6/13 H OW CAN WE U NDERSTAND OUR WATER R ESOURCES? Displaying data with graphs..
    [Show full text]