The hypothesis (CPH) refers to a long-standing debate in and over the extent to which the ability to acquire is linked to . The hypothesis claims that there is an ideal 'window' of time to acquire language in a linguistically rich environment, after which this is no longer possible due to changes in the . The hypothesis has been discussed in the context of both (FLA) and (SLA), and is particularly controversial in the latter. In FLA, it seeks to explain the apparent absence of language in individuals whose childhood exposure was very limited, and in SLA it is often invoked to explain variation in adults' performance in learning a second language, which is very often observed to fall short of attainment. Various ages have been proposed for the supposed end of the CPH; those that point to pre- ages such as 12 have been vulnerable to alternative theories which invoke or social factors applying as children move into .
The critical period hypothesis is associated with , whose 1956 Vanuxem lectures at formed the basis of his 1959 work with , . Penfield and Roberts explored the of language, concluding that it was dominant in the left hemisphere of the brain on the basis of hundreds of case studies spanning many decades. The review focussed on how individuals with brain damage evidenced atypical linguistic performance, rather than examining neurotypical cases of 'normal' language acquisition, and the authors' conclusions were also based on the prevailing view that children were born without any real language ability; however, linguistic "units", once "fixed", would affect later learning. Their recommendations for language schooling recommended starting early in order to avoid fixed effects; though these claims did not form the core of the book, being confined to the last chapter, other researchers and popular opinion were much-influenced by them. The hypothesis was developed by in his 1967 , which set the end of the critical period for native language acquisition at 12. The hypothesis has been fiercely debated since then, and has continued to inform popular assumptions about the presumed (in)ability of to learn a second language.
When you conduct a piece of quantitative research, you are inevitably attempting to answer a research question or hypothesis that you have set. One method of evaluating this research question is via a process called hypothesis testing, which is sometimes also referred to as significance testing. Since there are many facets to hypothesis testing, we start with the example we refer to throughout this guide.
For example, a particular hypothesis about meteorological interactions or nuclear reactions might be so complex that it is best described in the form of a computer program or a long mathematical equation.
Use the Internet or Strayer Library to research articles on hypothesis test and its application in business. Select one (1) company or organization which utilized hypothesis test technique for its business process (e.g., whether or not providing flexible work hours improve employee productivity.) Give your opinion as to whether or not the utilization of such a technique improved business process for the selected company or organization. Justify your response.
CORRECTION: Especially when it comes to scientific findings about health and medicine, it can sometimes seem as though scientists are always changing their minds. One month the newspaper warns you away from chocolate's saturated fat and sugar; the next month, chocolate companies are bragging about chocolate's antioxidants and lack of trans-fats. There are several reasons for such apparent reversals. First, press coverage tends to draw particular attention to disagreements or ideas that conflict with past views. Second, ideas at the cutting edge of research (e.g., regarding new medical studies) may change rapidly as scientists test out many different possible explanations trying to figure out which are the most accurate. This is a normal and healthy part of the process of science. While it's true that all scientific ideas are subject to change if warranted by the evidence, many scientific ideas (e.g., evolutionary theory, foundational ideas in chemistry) are supported by many lines of evidence, are extremely reliable, and are unlikely to change. To learn more about provisionality in science and its portrayal by the media, visit a section from our .
A further criticism of Krashen's theories is levelled at his repudiation of grammar instruction. Critics claim that some kind of direct focus on grammar is both beneficial and necessary - see Long (1998). Krashen (2003), after a comprehensive analysis of the research data in these two areas, concludes that neither learner output nor grammar focus have any direct influence on acquisition. He states that his hypotheses " .. have not only survived well over the years but have also proven to be useful in other areas of language education. So far, research results remain consistent with these hypotheses and there is no counterevidence."
CORRECTION: Perhaps because the last step of the Scientific Method is usually "draw a conclusion," it's easy to imagine that studies that don't reach a clear conclusion must not be scientific or important. In fact, scientific studies don't reach "firm" conclusions. Scientific articles usually end with a discussion of the limitations of the tests performed and the alternative hypotheses that might account for the phenomenon. That's the nature of scientific knowledge it's inherently tentative and could be overturned if new evidence, new interpretations, or a better explanation come along. In science, studies that carefully analyze the strengths and weaknesses of the test performed and of the different alternative explanations are particularly valuable since they encourage others to more thoroughly scrutinize the ideas and evidence and to develop new ways to test the ideas. To learn more about publishing and scrutiny in science, visit our discussion of .
: In everyday language, the word usually refers to an educated guess or an idea that we are quite uncertain about. Scientific hypotheses, however, are much more informed than any guess and are usually based on prior experience, scientific background knowledge, preliminary observations, and logic. In addition, hypotheses are often supported by many different lines of evidence in which case, scientists are more confident in them than they would be in any mere "guess." To further complicate matters, science textbooks frequently misuse the term in a slightly different way. They may ask students to make a about the outcome of an experiment (e.g., table salt will dissolve in water more quickly than rock salt will). This is simply a prediction or a guess (even if a well-informed one) about the outcome of an experiment. Scientific hypotheses, on the other hand, have explanatory power they are explanations for phenomena. The idea that table salt dissolves faster than rock salt is not very hypothesis-like because it is not very explanatory. A more scientific (i.e., more explanatory) hypothesis might be "The amount of surface area a substance has affects how quickly it can dissolve. More surface area means a faster rate of dissolution." This hypothesis has some explanatory power it gives us an idea of a particular phenomenon occurs and it is testable because it generates expectations about what we should observe in different situations. If the hypothesis is accurate, then we'd expect that, for example, sugar processed to a powder should dissolve more quickly than granular sugar. Students could examine rates of dissolution of many different substances in powdered, granular, and pellet form to further test the idea. The statement "Table salt will dissolve in water more quickly than rock salt" is not a hypothesis, but an expectation generated by a hypothesis. Textbooks and science labs can lead to confusions about the difference between a hypothesis and an expectation regarding the outcome of a scientific test. To learn more about scientific hypotheses, visit in our section on how science works.
CORRECTION: It's easy to think that what scientists do in far-off laboratories and field stations has little relevance to your everyday life after all, not many of us deal with super colliders or arctic plankton on a regular basis but take another look around you. All the technologies, medical advances, and knowledge that improve our lives everyday are partly the result of scientific research. Furthermore, the choices you make when you vote in elections and support particular causes can influence the course of science. Science is deeply interwoven with our everyday lives. To see how society influences science, visit . To learn more about how scientific advances affect your life, visit