Friday, February 14, 2014

The conjecture might be that a new

The conjecture might be that a new drug will cure the disease in some of those people. Terms commonly associated with statistical hypotheses are null hypothesis and alternative hypothesis. A null hypothesis is the conjecture that the statistical hypothesis is false, e.g.,HP Pavilion DV6-1030us Laptop Keyboard that the new drug does nothing and that any cures are due to chance effects. Researchers normally want to show that the null hypothesis is false. The alternative hypothesis is the desired outcome, e.g., that the drug does better than chance. DELL Vostro 1510 Laptop Keyboard A final point: a scientific hypothesis must be falsifiable, meaning that one can identify a possible outcome of an experiment that conflicts with predictions deduced from the hypothesis; otherwise, it cannot be meaningfully tested.DELL Vostro 1014 Laptop Keyboard Prediction: This step involves determining the logical consequences of the hypothesis. One or more predictions are then selected for further testing. The less likely that the prediction would be correct simply by coincidence, the stronger evidence it would be if the prediction were fulfilled; evidence is also stronger if the answer to the prediction is not already known, DELL PVDG3 Laptop Keyboard due to the effects of hindsight bias (see also postdiction). Ideally, the prediction must also distinguish the hypothesis from likely alternatives; if two hypotheses make the same prediction, observing the prediction to be correct is not evidence for either one over the other. (These statements about the relative strength of evidence can be mathematically derived using Bayes' Theorem.)DELL Vostro 3450 Laptop Keyboard Testing: This is an investigation of whether the real world behaves as predicted by the hypothesis. Scientists (and other people) test hypotheses by conducting experiments. The purpose of an experiment is to determine whether observations of the real world agree with or conflict with the predictions derived from an hypothesis.  DELL 0PVDG3 Laptop Keyboard If they agree, confidence in the hypothesis increases; otherwise, it decreases. Agreement does not assure that the hypothesis is true; future experiments may reveal problems. Karl Popper advised scientists to try to falsify hypotheses, i.e.,ACER Aspire 5652WLMi Laptop Keyboard to search for and test those experiments that seem most doubtful. Large numbers of successful confirmations are not convincing if they arise from experiments that avoid risk.[21] Experiments should be designed to minimize possible errors,  SONY VAIO VGN-NW240F Laptop Keyboard especially through the use of appropriatescientific controls. For example, tests of medical treatments are commonly run as double-blind tests. Test personnel, who might unwittingly reveal to test subjects which samples are the desired test drugs and which are placebos, are kept ignorant of which are which. Such hints can bias the responses of the test subjects.  ACER KB.TNT07.002 Laptop Keyboard Furthermore, failure of an experiment does not necessarily mean the hypothesis is false. Experiments always depend on several hypotheses, e.g., that the test equipment is working properly, and a failure may be a failure of one of the auxiliary hypotheses. (See the Duhem-Quine thesis.) HP Mini 311-1033CA laptop keyboard Experiments can be conducted in a college lab, on a kitchen table, at CERN's Large Hadron Collider, at the bottom of an ocean, on Mars (using one of the working rovers), and so on. Astronomers do experiments, searching for planets around distant stars. HP Pavilion dv6-3022ee laptop keyboard Finally, most individual experiments address highly specific topics for reasons of practicality. As a result, evidence about broader topics is usually accumulated gradually. Analysis: This involves determining what the results of the experiment show and deciding on the next actions to take. SONY VAIO VGN-CS17G/R laptop keyboard The predictions of the hypothesis are compared to those of the null hypothesis, to determine which is better able to explain the data. In cases where an experiment is repeated many times, astatistical analysis such as a chi-squared test may be required. SONY VAIO VGN-FS790 laptop keyboard If the evidence has falsified the hypothesis, a new hypothesis is required; if the experiment supports the hypothesis but the evidence is not strong enough for high confidence, other predictions from the hypothesis must be tested. Once a hypothesis is strongly supported by evidence, a new question can be asked to provide further insight on the same topic.SONY VAIO VGN-N385E laptop keyboard Evidence from other scientists and experience are frequently incorporated at any stage in the process. Depending on the complexity of the experiment, many iterations may be required to gather sufficient evidence to answer a question with confidence, or to build up many answers to highly specific questions in order to answer a single broader question.SONY VAIO VGN-CR220Q laptop keyboard The scientific method also includes other components required even when all the iterations of the steps above have been completed:[citation needed] Replication: If an experiment cannot be repeated to produce the same results, this implies that the original results were in error.  SONY VAIO VGN-CR220E laptop keyboard As a result, it is common for a single experiment to be performed multiple times, especially when there are uncontrolled variables or other indications of experimental error. For significant or surprising results, other scientists may also attempt to replicate the results for themselves, especially if those results would be important to their own work.[citation needed]SONY 148701322 laptop keyboard External review: The process of peer review involves evaluation of the experiment by experts, who give their opinions anonymously to allow them to give unbiased criticism. It does not certify correctness of the results, only that the experiments themselves were sound (based on the description supplied by the experimenter). LENOVO IdeaPad S10 4231 laptop keyboard If the work passes peer review, which may require new experiments requested by the reviewers, it will be published in a peer-reviewedscientific journal. The specific journal that publishes the results indicates the perceived quality of the work.[citation needed]HP Pavilion dv6-3110se laptop keyboard Data recording and sharing: Scientists must record all data very precisely in order to reduce their own bias and aid in replication by others, a requirement first promoted by Ludwik Fleck (1896–1961) and others.[34] ASUS V020662BS1 laptop keyboard They must supply this data to other scientists who wish to replicate any results, extending to the sharing of any experimental samples that may be difficult to obtain.[35] The goal of a scientific inquiry is to obtain knowledge in the form of testable explanations that can predict the results of future experiments. IBM 42T3265 laptop keyboard This allows scientists to gain an understanding of reality, and later use that understanding to intervene in its causal mechanisms (such as to cure disease). The better an explanation is at making predictions, the more useful it is, and the more likely it is to be correct. TOSHIBA Satellite L675-S7044 laptop keyboard The most successful explanations, which explain and make accurate predictions in a wide range of circumstances, are called scientific theories. Most experimental results do not result in large changes in human understanding; improvements in theoretical scientific understanding is usually the result of a gradual synthesis of the results of different experiments, by various researchers, across different domains of science.[36]  FUJITSU Amilo Mini Ui 3520 laptop keyboard Scientific models vary in the extent to which they have been experimentally tested and for how long, and in their acceptance in the scientific community. In general, explanations become accepted by a scientific community as evidence in favor is presented, and as presumptions that are inconsistent with the evidence are falsified.SONY Vaio PCG-K33 Laptop Keyboard Scientific knowledge is closely tied to empirical findings, and always remains subject to falsification if new experimental observation incompatible with it is found. That is, no theory can ever be considered completely certain, Lenovo ThinkPad Edge E520 Laptop Keyboard since new evidence falsifying it might be discovered. If such evidence is found, a new theory may be proposed, or (more commonly) it is found that minor modifications to the previous theory are sufficient to explain the new evidence. The strength of a theory is related to how long it has persisted without falsification of its core principles.TOSHIBA 6037b0026805 Laptop Keyboard Confirmed theories are also subject to subsumption by more accurate theories. For example, thousands of years of scientific observations of the planets were explained almost perfectly by Newton's laws. However, these laws were then determined to be special cases of a more general theory (relativity), ACER Aspire 4736ZG Laptop CPU Cooling Fan which explained both the (previously unexplained) exceptions to Newton's laws as well as predicting and explaining other observations such as the deflection of light by gravity. Thus independent, unconnected, scientific observations can be connected to each other, unified by principles of increasing explanatory power.[37] HP Pavilion dv4-1133tx Laptop CPU Cooling Fan Since every new theory must explain even more than the previous one, any successor theory capable of subsuming it must meet an even higher standard, explaining both the larger, unified body of observations explained by the previous theory and unifying that with even more observations.  HP Pavilion dv6-3043ee Laptop CPU Cooling Fan In other words, as scientific knowledge becomes more accurate with time, it becomes increasingly harder to produce a more successful theory, simply because of the great success of the theories that already exist.[37] For example, the theory of evolution explains the diversity of life on Earth, how species adapt to their environments,  Compaq Presario CQ61-421SG Laptop CPU Cooling Fan and many other patterns observed in the natural world;[38][39] its most recent major modification was unification with genetics to form the modern evolutionary synthesis. In subsequent modifications, it has also subsumed aspects of many other fields such as biochemistry and molecular biology. HP Pavilion dv6-1101au Laptop CPU Cooling Fan Beliefs and biases Scientific methodology directs that hypotheses be tested in controlled conditions which can be reproduced by others. Thescientific community's pursuit of experimental control and reproducibility diminishes the effects of cognitive biases.HP Pavilion dv6-3125er Laptop CPU Cooling Fan For example, pre-existing beliefs can alter the interpretation of results, as in confirmation bias; this is a heuristic that leads a person with a particular belief to see things as reinforcing their belief, even if another observer might disagree (in other words, people tend to observe what they expect to observe).HP 606575-001 Laptop CPU Cooling Fan A historical example is the conjecture that the legs of a galloping horse are splayed at the point when none of the horse's legs touches the ground, to the point of this image being included in paintings by its supporters.  HP Pavilion dv7-6185us Laptop CPU Cooling Fan However, the first stop-action pictures of a horse's gallop by Eadweard Muybridge showed this to be false, and that the legs are instead gathered together.[40] Another important human bias that plays a role is a preference for new, surprising statements (see appeal to novelty), which can result in a search for evidence that the new is true.[1]DELL DFS491105MH0T Laptop CPU Cooling Fan In contrast to the requirement for scientific knowledge to correspond to reality, beliefs based on myth or stories can be believed and acted upon irrespective of truth,[41] often taking advantage of the narrative fallacy that when narrative is constructed its elements become easier to believe.[42][43] HP 532613-001 Laptop CPU Cooling Fan Myths intended to be taken as true must have their elements assumed a priori, while science requires testing and validation a posteriori before ideas are accepted.[44] There are different ways of outlining the basic method used for scientific inquiry. Compaq Presario CQ60-417DX Laptop CPU Cooling Fan The scientific community and philosophers of science generally agree on the following classification of method components. These methodological elements and organization of procedures tend to be more characteristic of natural sciencesthan social sciences. HP Pavilion dv7-3060us Laptop CPU Cooling Fan Nonetheless, the cycle of formulating hypotheses, testing and analyzing the results, and formulating new hypotheses, will resemble the cycle described below. Each element of the scientific method is subject to peer review for possible mistakes. HP KSB06105HA Laptop CPU Cooling Fan These activities do not describe all that scientists do (see below) but apply mostly to experimental sciences (e.g., physics, chemistry, and biology). The elements above are often taught in the educational system as "the scientific method".[58]Dell Latitude E6510 Laptop CPU Cooling Fan The scientific method is not a single recipe: it requires intelligence, imagination, and creativity.[59] In this sense, it is not a mindless set of standards and procedures to follow, but is rather an ongoing cycle, constantly developing more useful, accurate and comprehensive models and methods. HP 441541-001 Laptop Keyboard For example, when Einstein developed the Special and General Theories of Relativity, he did not in any way refute or discount Newton's Principia. On the contrary, if the astronomically large, the vanishingly small,  TOSHIBA Satellite l25-s1196 laptop keyboard and the extremely fast are removed from Einstein's theories – all phenomena Newton could not have observed – Newton's equations are what remain. Einstein's theories are expansions and refinements of Newton's theories and, thus, increase our confidence in Newton's work.SONY VAIO VGN-CS11S/W laptop keyboard A linearized, pragmatic scheme of the four points above is sometimes offered as a guideline for proceeding:[60] Measurements demand the use of operational definitions of relevant quantities. That is, a scientific quantity is described or defined by how it is measured,DELL Inspiron 1750 Laptop Keyboard as opposed to some more vague, inexact or "idealized" definition. For example, electrical current, measured in amperes, may be operationally defined in terms of the mass of silver deposited in a certain time on an electrode in an electrochemical device that is described in some detail. HP Envy 15 Laptop Keyboard The operational definition of a thing often relies on comparisons with standards: the operational definition of "mass" ultimately relies on the use of an artifact, such as a particular kilogram of platinum-iridium kept in a laboratory in France.HP Pavilion dv6-3022ee Laptop Keyboard The scientific definition of a term sometimes differs substantially from its natural language usage. For example, mass and weight overlap in meaning in common discourse, but have distinct meanings in mechanics. SONY VAIO VGN-CS17G/Q Laptop Keyboard Scientific quantities are often characterized by their units of measure which can later be described in terms of conventional physical units when communicating the work. New theories are sometimes developed after realizing certain terms have not previously been sufficiently clearly defined. For example,DELL PVDG3 Laptop Keyboard Albert Einstein's first paper on relativity begins by defining simultaneity and the means for determining length. These ideas were skipped over by Isaac Newton with, "I do not definetime, space, place and motion, as being well known to all." Einstein's paper then demonstrates that they (viz., absolute time and length independent of motion) were approximations.HP Mini 1001TU Laptop Keyboard Francis Crick cautions us that when characterizing a subject, however, it can be premature to define something when it remains ill-understood.SONY 148701322 Laptop Keyboard His cautionary example was the gene; the gene was much more poorly understood before Watson and Crick's pioneering discovery of the structure of DNA; it would have been counterproductive to spend much time on the definition of the gene, before them. HP G71-445US Laptop Keyboard An hypothesis is a suggested explanation of a phenomenon, or alternately a reasoned proposal suggesting a possible correlation between or among a set of phenomena. Normally hypotheses have the form of a mathematical model. Sometimes, but not always, they can also be formulated as existential statements, COMPAQ Presario CQ41-205TU Laptop Keyboard stating that some particular instance of the phenomenon being studied has some characteristic and causal explanations, which have the general form of universal statements, stating that every instance of the phenomenon has a particular characteristic.ACER Travelmate 8571 Laptop Keyboard Scientists are free to use whatever resources they have – their own creativity, ideas from other fields, induction, Bayesian inference, and so on – to imagine possible explanations for a phenomenon under study. Charles Sanders Peirce,HP Mini 110-1169TU Laptop Keyboard borrowing a page from Aristotle (Prior Analytics, 2.25) described the incipient stages of inquiry, instigated by the "irritation of doubt" to venture a plausible guess, as abductive reasoning. The history of science is filled with stories of scientists claiming a "flash of inspiration", or a hunch, HP AEUT3U00020 Laptop Keyboard which then motivated them to look for evidence to support or refute their idea. Michael Polanyimade such creativity the centerpiece of his discussion of methodology. William Glen observes that HP Pavilion DV7-3069wm Laptop Keyboard the success of a hypothesis, or its service to science, lies not simply in its perceived "truth", or power to displace, subsume or reduce a predecessor idea, but perhaps more in its ability to stimulate the research that will illuminate … bald suppositions and areas of vagueness.[66]HP 636376-001 Laptop Keyboard In general scientists tend to look for theories that are "elegant" or "beautiful". In contrast to the usual English use of these terms, they here refer to a theory in accordance with the known facts, which is nevertheless relatively simple and easy to handle. Occam's Razor serves as a rule of thumb for choosing the most desirable amongst a group of equally explanatory hypotheses.HP 576835-001 Laptop Keyboard Any useful hypothesis will enable predictions, by reasoning including deductive reasoning. It might predict the outcome of an experiment in a laboratory setting or the observation of a phenomenon in nature. The prediction can also be statistical and deal only with probabilities. HP G56-118CA Laptop Keyboard It is essential that the outcome of testing such a prediction be currently unknown. Only in this case does a successful outcome increase the probability that the hypothesis is true. If the outcome is already known, it is called a consequence and should have already been considered while formulating the hypothesis.TOSHIBA Satellite A200-1DN laptop keyboard, TOSHIBA 6037b0026805 laptop keyboard

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